## Pagoda: Rapid, easy full-stack web development starter kit in Go
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## Table of Contents
* [Introduction](#introduction)
* [Overview](#overview)
* [Foundation](#foundation)
* [Backend](#backend)
* [Frontend](#frontend)
* [Storage](#storage)
* [Screenshots](#screenshots)
* [Getting started](#getting-started)
* [Dependencies](#dependencies)
* [Start the application](#start-the-application)
* [Running tests](#running-tests)
* [Service container](#service-container)
* [Dependency injection](#dependency-injection)
* [Test dependencies](#test-dependencies)
* [Configuration](#configuration)
* [Environment overrides](#environment-overrides)
* [Environments](#environments)
* [Database](#database)
* [Auto-migrations](#auto-migrations)
* [Separate test database](#separate-test-database)
* [SQLC](#sqlc)
* [Sessions](#sessions)
* [Encryption](#encryption)
* [Authentication](#authentication)
* [Login / Logout](#login--logout)
* [Forgot password](#forgot-password)
* [Registration](#registration)
* [Authenticated user](#authenticated-user)
* [Middleware](#middleware)
* [Email verification](#email-verification)
* [Routes](#routes)
* [Custom middleware](#custom-middleware)
* [Handlers](#handlers)
* [Errors](#errors)
* [Testing](#testing)
* [HTTP server](#http-server)
* [Request / Request helpers](#request--response-helpers)
* [Goquery](#goquery)
* [Pages](#pages)
* [Flash messaging](#flash-messaging)
* [Pager](#pager)
* [CSRF](#csrf)
* [Automatic template parsing](#automatic-template-parsing)
* [Cached responses](#cached-responses)
* [Cache tags](#cache-tags)
* [Cache middleware](#cache-middleware)
* [Data](#data)
* [Forms](#forms)
* [Submission processing](#submission-processing)
* [Inline validation](#inline-validation)
* [Headers](#headers)
* [Status code](#status-code)
* [Metatags](#metatags)
* [URL and link generation](#url-and-link-generation)
* [HTMX support](#htmx-support)
* [Rendering the page](#rendering-the-page)
* [Template renderer](#template-renderer)
* [Custom functions](#custom-functions)
* [Caching](#caching)
* [Hot-reload for development](#hot-reload-for-development)
* [File configuration](#file-configuration)
* [Funcmap](#funcmap)
* [Cache](#cache)
* [Set data](#set-data)
* [Get data](#get-data)
* [Flush data](#flush-data)
* [Flush tags](#flush-tags)
* [Tasks](#tasks)
* [Queues](#queues)
* [Dispatcher](#dispatcher)
* [Cron](#cron)
* [Static files](#static-files)
* [Cache control headers](#cache-control-headers)
* [Cache-buster](#cache-buster)
* [Email](#email)
* [HTTPS](#https)
* [Logging](#logging)
* [Roadmap](#roadmap)
* [Credits](#credits)
* [Similar Projects](#similar-projects)
## Introduction
### Overview
_Pagoda_ is not a framework but rather a base starter-kit for rapid, easy full-stack web development in Go, aiming to provide much of the functionality you would expect from a complete web framework as well as establishing patterns, procedures and structure for your web application.
Built on a solid [foundation](#foundation) of well-established frameworks and modules, _Pagoda_ aims to be a starting point for any web application with the benefit over a mega-framework in that you have full control over all of the code, the ability to easily swap any frameworks or modules in or out, no strict patterns or interfaces to follow, and no fear of lock-in.
While separate JavaScript frontends have surged in popularity, many prefer the reliability, simplicity and speed of a full-stack approach with server-side rendered HTML. Even the popular JS frameworks all have SSR options. This project aims to highlight that _Go_ templates can be powerful and easy to work with, and interesting [frontend](#frontend) libraries can provide the same modern functionality and behavior without having to write any JS at all.
### Foundation
While many great projects were used to build this, all of which are listed in the [credits](#credits) section, the following provide the foundation of the back and frontend. It's important to note that you are **not required to use any of these**. Swapping any of them out will be relatively easy.
#### Backend
- [Echo](https://echo.labstack.com/): High performance, extensible, minimalist Go web framework.
- [Ent](https://entgo.io/): Simple, yet powerful ORM for modeling and querying data.
#### Frontend
Go server-side rendered HTML combined with the projects below enable you to create slick, modern UIs without writing any JavaScript or CSS.
- [HTMX](https://htmx.org/): Access AJAX, CSS Transitions, WebSockets and Server Sent Events directly in HTML, using attributes, so you can build modern user interfaces with the simplicity and power of hypertext.
- [Alpine.js](https://alpinejs.dev/): Rugged, minimal tool for composing behavior directly in your markup. Think of it like jQuery for the modern web. Plop in a script tag and get going.
- [Bulma](https://bulma.io/): Provides ready-to-use frontend components that you can easily combine to build responsive web interfaces. No JavaScript dependencies.
#### Storage
- [SQLite](https://sqlite.org/): A small, fast, self-contained, high-reliability, full-featured, SQL database engine and the most used database engine in the world.
Originally, Postgres and Redis were chosen as defaults but since the aim of this project is rapid, simple development, it was changed to SQLite which now provides the primary data storage as well as persistent, background [task queues](#tasks). For [caching](#cache), a simple in-memory solution is provided. If you need to use something like Postgres or Redis, swapping those in can be done quickly and easily. For reference, [this branch](https://github.com/mikestefanello/pagoda/tree/postgres-redis) contains the code that included those (but is no longer maintained).
### Screenshots
#### Inline form validation
#### Switch layout templates, user registration
#### Alpine.js modal, HTMX AJAX request
## Getting started
### Dependencies
Ensure that [Go](https://go.dev/) is installed on your system.
### Start the application
After checking out the repository, from within the root, simply run `make run`:
```
git clone git@github.com:mikestefanello/pagoda.git
cd pagoda
make run
```
Since this repository is a _template_ and not a Go _library_, you **do not** use `go get`.
By default, you should be able to access the application in your browser at `localhost:8000`. This can be changed via the [configuration](#configuration).
By default, your data will be stored within the `dbs` directory. If you ever want to quickly delete all data just remove this directory.
### Running tests
To run all tests in the application, execute `make test`. This ensures that the tests from each package are not run in parallel. This is required since many packages contain tests that connect to the test database which is stored in memory and reset automatically for each package.
## Service container
The container is located at `pkg/services/container.go` and is meant to house all of your application's services and/or dependencies. It is easily extensible and can be created and initialized in a single call. The services currently included in the container are:
- Configuration
- Cache
- Database
- Web
- Validator
- Authentication
- Mail
- Template renderer
- Tasks
A new container can be created and initialized via `services.NewContainer()`. It can be later shutdown via `Shutdown()`.
### Dependency injection
The container exists to faciliate easy dependency-injection both for services within the container as well as areas of your application that require any of these dependencies. For example, the container is automatically passed to the `Init()` method of your route [handlers](#handlers) so that the handlers have full, easy access to all services.
### Test dependencies
It is common that your tests will require access to dependencies, like the database, or any of the other services available within the container. Keeping all services in a container makes it especially easy to initialize everything within your tests. You can see an example pattern for doing this [here](#environments).
## Configuration
The `config` package provides a flexible, extensible way to store all configuration for the application. Configuration is added to the `Container` as a _Service_, making it accessible across most of the application.
Be sure to review and adjust all of the default configuration values provided in `config/config.yaml`.
### Environment overrides
Leveraging the functionality of [viper](https://github.com/spf13/viper) to manage configuration, all configuration values can be overridden by environment variables. The name of the variable is determined by the set prefix and the name of the configuration field in `config/config.yaml`.
In `config/config.go`, the prefix is set as `pagoda` via `viper.SetEnvPrefix("pagoda")`. Nested fields require an underscore between levels. For example:
```yaml
http:
port: 1234
```
can be overridden by setting an environment variable with the name `PAGODA_HTTP_PORT`.
### Environments
The configuration value for the current _environment_ (`Config.App.Environment`) is an important one as it can influence some behavior significantly (will be explained in later sections).
A helper function (`config.SwitchEnvironment`) is available to make switching the environment easy, but this must be executed prior to loading the configuration. The common use-case for this is to switch the environment to `Test` before tests are executed:
```go
func TestMain(m *testing.M) {
// Set the environment to test
config.SwitchEnvironment(config.EnvTest)
// Start a new container
c = services.NewContainer()
// Run tests
exitVal := m.Run()
// Shutdown the container
if err := c.Shutdown(); err != nil {
panic(err)
}
os.Exit(exitVal)
}
```
## Database
The database currently used is [SQLite](https://sqlite.org/) but you are free to use whatever you prefer. The database driver is provided by [go-sqlite3](https://github.com/mattn/go-sqlite3). A reference to the database is included in the `Container` if direct access is required.
Database configuration can be found and managed within the `config` package.
### Auto-migrations
[Golang Migrate](github.com/golang-migrate/migrate) provides automati migrat-ns on the database whenever the application starts. Migrations are written in the `db/migrations` directory, which must be present at runtime in the container.
### Separate test database
Since many tests can require a database, this application supports a separate database specifically for tests. Within the `config`, the test database can be specified at `Config.Database.TestConnection`, which is the database connection string that will be used. By default, this will be an in-memory SQLite database.
When a `Container` is created, if the [environment](#environments) is set to `config.EnvTest`, the database client will connect to the test database instead and run migrations so your tests start with a clean, ready-to-go database.
When this project was using Postgres, it would automatically drop and recreate the test database. Since the current default is in-memory, that is no longer needed. If you decide to use a test database not in-memory, you can alter the `Container` initialization code to do this for you.
## SQLC
Database interactions are handled using [sqlc](https://sqlc.dev) by writing raw SQL queries in the `database/queries` directory and then generating the necessary boilerplate code with `make sqlc`. This creates functions available on the `DBClient.C` object for each written query.
If you want to group business logic for the database into functions beyond what can be performed in a single SQL query, you can create a sub-client, such as the example`DBUserClient` and attach methods which have access to the database.
## Sessions
Sessions are provided and handled via [Gorilla sessions](https://github.com/gorilla/sessions) and configured as middleware in the router located at `pkg/handlers/router.go`. Session data is currently stored in cookies but there are many [options](https://github.com/gorilla/sessions#store-implementations) available if you wish to use something else.
Here's a simple example of loading data from a session and saving new values:
```go
func SomeFunction(ctx echo.Context) error {
sess, err := session.Get(ctx, "some-session-key")
if err != nil {
return err
}
sess.Values["hello"] = "world"
sess.Values["isSomething"] = true
return sess.Save(ctx.Request(), ctx.Response())
}
```
### Encryption
Session data is encrypted for security purposes. The encryption key is stored in [configuration](#configuration) at `Config.App.EncryptionKey`. While the default is fine for local development, it is **imperative** that you change this value for any live environment otherwise session data can be compromised.
## Authentication
Included are standard authentication features you expect in any web application. Authentication functionality is bundled as a _Service_ within `services/AuthClient` and added to the `Container`. If you wish to handle authentication in a different manner, you could swap this client out or modify it as needed.
Authentication currently requires [sessions](#sessions) and the session middleware.
### Login / Logout
The `AuthClient` has methods `Login()` and `Logout()` to log a user in or out. To track a user's authentication state, data is stored in the session including the user ID and authentication status.
Prior to logging a user in, the method `CheckPassword()` can be used to determine if a user's password matches the hash stored in the database and on the `User` entity.
Routes are provided for the user to login and logout at `user/login` and `user/logout`.
### Forgot password
Users can reset their password in a secure manner by issuing a new password token via the method `GeneratePasswordResetToken()`. This creates a new `PasswordToken` entity in the database belonging to the user. The actual token itself, however, is not stored in the database for security purposes. It is only returned via the method so it can be used to build the reset URL for the email. Rather, a hash of the token is stored, using `bcrypt` the same package used to hash user passwords. The reason for doing this is the same as passwords. You do not want to store a plain-text value in the database that can be used to access an account.
Tokens have a configurable expiration. By default, they expire within 1 hour. This can be controlled in the `config` package. The expiration of the token is not stored in the database, but rather is used only when tokens are loaded for potential usage. This allows you to change the expiration duration and affect existing tokens.
Since the actual tokens are not stored in the database, the reset URL must contain the user and password token ID. Using that, `GetValidPasswordToken()` will load a matching, non-expired _password token_ entity belonging to the user, and use `bcrypt` to determine if the token in the URL matches stored hash of the password token entity.
Once a user claims a valid password token, all tokens for that user should be deleted using `DeletePasswordTokens()`.
Routes are provided to request a password reset email at `user/password` and to reset your password at `user/password/reset/token/:user/:password_token/:token`.
### Registration
The actual registration of a user is not handled within the `AuthClient` but rather just by creating a `User` entity. When creating a user, use `HashPassword()` to create a hash of the user's password, which is what will be stored in the database.
A route is provided for the user to register at `user/register`.
### Authenticated user
The `AuthClient` has two methods available to get either the `User` entity or the ID of the user currently logged in for a given request. Those methods are `GetAuthenticatedUser()` and `GetAuthenticatedUserID()`.
#### Middleware
Registered for all routes is middleware that will load the currently logged in user entity and store it within the request context. The middleware is located at `middleware.LoadAuthenticatedUser()` and, if authenticated, the `User` entity is stored within the context using the key `context.AuthenticatedUserKey`.
If you wish to require either authentication or non-authentication for a given route, you can use either `middleware.RequireAuthentication()` or `middleware.RequireNoAuthentication()`.
### Email verification
Most web applications require the user to verify their email address (or other form of contact information). The `User` entity has a field `Verified` to indicate if they have verified themself. When a user successfully registers, an email is sent to them containing a link with a token that will verify their account when visited. This route is currently accessible at `/email/verify/:token` and handled by `pkg/handlers/auth.go`.
There is currently no enforcement that a `User` must be verified in order to access the application. If that is something you desire, it will have to be added in yourself. It was not included because you may want partial access of certain features until the user verifies; or no access at all.
Verification tokens are [JSON Web Tokens](https://jwt.io/) generated and processed by the [jwt](https://github.com/golang-jwt/jwt) module. The tokens are _signed_ using the encryption key stored in [configuration](#configuration) (`Config.App.EncryptionKey`). **It is imperative** that you override this value from the default in any live environments otherwise the data can be comprimised. JWT was chosen because they are secure tokens that do not have to be stored in the database, since the tokens contain all of the data required, including built-in expirations. These were not chosen for password reset tokens because JWT cannot be withdrawn once they are issued which poses a security risk. Since these tokens do not grant access to an account, the ability to withdraw the tokens is not needed.
By default, verification tokens expire 12 hours after they are issued. This can be changed in configuration at `Config.App.EmailVerificationTokenExpiration`. There is currently not a route or form provided to request a new link.
Be sure to review the [email](#email) section since actual email sending is not fully implemented.
To generate a new verification token, the `AuthClient` has a method `GenerateEmailVerificationToken()` which creates a token for a given email address. To verify the token, pass it in to `ValidateEmailVerificationToken()` which will return the email address associated with the token and an error if the token is invalid.
## Routes
The router functionality is provided by [Echo](https://echo.labstack.com/guide/routing/) and constructed within via the `BuildRouter()` function inside `pkg/handlers/router.go`. Since the _Echo_ instance is a _Service_ on the `Container` which is passed in to `BuildRouter()`, middleware and routes can be added directly to it.
### Custom middleware
By default, a middleware stack is included in the router that makes sense for most web applications. Be sure to review what has been included and what else is available within _Echo_ and the other projects mentioned.
A `middleware` package is included which you can easily add to along with the custom middleware provided.
### Handlers
A `Handler` is a simple type that handles one or more of your routes and allows you to group related routes together (ie, authentication). All provided handlers are located in `pkg/handlers`. _Handlers_ also handle self-registering their routes with the router.
#### Example
The provided patterns are not required, but were designed to make development as easy as possible.
For this example, we'll create a new handler which includes a GET and POST route and uses the database. Start by creating a file at `pkg/handlers/example.go`.
1) Define the handler type:
```go
type Example struct {
db *services.DBClient
*services.TemplateRenderer
}
```
2) Register the handler so the router automatically includes it
```go
func init() {
Register(new(Example))
}
```
3) Initialize the handler (and inject any required dependencies from the _Container_). This will be called automatically.
```go
func (e *Example) Init(c *services.Container) error {
e.TemplateRenderer = c.TemplateRenderer
e.db = c.DB
return nil
}
```
4) Declare the routes
**It is highly recommended** that you provide a `Name` for your routes. Most methods on the back and frontend leverage the route name and parameters in order to generate URLs.
```go
func (e *Example) Routes(g *echo.Group) {
g.GET("/example", e.Page).Name = "example"
g.POST("/example", c.PageSubmit).Name = "example.submit"
}
```
5) Implement your routes
```go
func (e *Example) Page(ctx echo.Context) error {
// add your code here
}
func (e *Example) PageSubmit(ctx echo.Context) error {
// add your code here
}
```
### Errors
Routes can return errors to indicate that something wrong happened. Ideally, the error is of type `*echo.HTTPError` to indicate the intended HTTP response code. You can use `return echo.NewHTTPError(http.StatusInternalServerError)`, for example. If an error of a different type is returned, an _Internal Server Error_ is assumed.
The [error handler](https://echo.labstack.com/guide/error-handling/) is set to the provided `Handler` in `pkg/handlers/error.go` in the `BuildRouter()` function. That means that if any middleware or route return an error, the request gets routed there. This route conveniently constructs and renders a `Page` which uses the template `templates/pages/error.gohtml`. The status code is passed to the template so you can easily alter the markup depending on the error type.
### Redirects
The `pkg/redirect` package makes it easy to perform redirects, especially if you provide names for your routes. The `Redirect` type provides the ability to chain redirect options and also supports automatically handling HTMX redirects for boosted requests.
For example, if your route name is `user_profile` with a URL pattern of `/user/profile/:id`, you can perform a redirect by doing:
```go
return redirect.New(ctx).
Route("user_profile").
Params(userID).
Query(queryParams).
Go()
```
### Testing
Since most of your web application logic will live in your routes, being able to easily test them is important. The following aims to help facilitate that.
The test setup and helpers reside in `pkg/handlers/router_test.go`.
Only a brief example of route tests were provided in order to highlight what is available. Adding full tests did not seem logical since these routes will most likely be changed or removed in your project.
#### HTTP server
When the route tests initialize, a new `Container` is created which provides full access to all of the _Services_ that will be available during normal application execution. Also provided is a test HTTP server with the router added. This means your tests can make requests and expect responses exactly as the application would behave outside of tests. You do not need to mock the requests and responses.
#### Request / Response helpers
With the test HTTP server setup, test helpers for making HTTP requests and evaluating responses are made available to reduce the amount of code you need to write. See `httpRequest` and `httpResponse` within `pkg/handlers/router_test.go`.
Here is an example how to easily make a request and evaluate the response:
```go
func TestAbout_Get(t *testing.T) {
doc := request(t).
setRoute("about").
get().
assertStatusCode(http.StatusOK).
toDoc()
}
```
#### Goquery
A helpful, included package to test HTML markup from HTTP responses is [goquery](https://github.com/PuerkitoBio/goquery). This allows you to use jQuery-style selectors to parse and extract HTML values, attributes, and so on.
In the example above, `toDoc()` will return a `*goquery.Document` created from the HTML response of the test HTTP server.
Here is a simple example of how to use it, along with [testify](https://github.com/stretchr/testify) for making assertions:
```go
h1 := doc.Find("h1.title")
assert.Len(t, h1.Nodes, 1)
assert.Equal(t, "About", h1.Text())
```
## Pages
The `Page` is the major building block of your `Handler` responses. It is a _struct_ type located at `pkg/page/page.go`. The concept of the `Page` is that it provides a consistent structure for building responses and transmitting data and functionality to the templates. Pages are rendered with the `TemplateRenderer`.
All example routes provided construct and _render_ a `Page`. It's recommended that you review both the `Page` and the example routes as they try to illustrate all included functionality.
As you develop your application, the `Page` can be easily extended to include whatever data or functions you want to provide to your templates.
Initializing a new page is simple:
```go
func (c *home) Get(ctx echo.Context) error {
p := page.New(ctx)
}
```
Using the `echo.Context`, the `Page` will be initialized with the following fields populated:
- `Context`: The passed in _context_
- `Path`: The requested URL path
- `URL`: The requested URL
- `StatusCode`: Defaults to 200
- `Pager`: Initialized `Pager` (see below)
- `RequestID`: The request ID, if the middleware is being used
- `IsHome`: If the request was for the homepage
- `IsAuth`: If the user is authenticated
- `AuthUser`: The logged in user entity, if one
- `CSRF`: The CSRF token, if the middleware is being used
- `HTMX.Request`: Data from the HTMX headers, if HTMX made the request (see below)
### Flash messaging
Flash messaging functionality is provided within the `msg` package. It is used to provide one-time status messages to users.
Flash messaging requires that [sessions](#sessions) and the session middleware are in place since that is where the messages are stored.
#### Creating messages
There are four types of messages, and each can be created as follows:
- Success: `msg.Success(ctx echo.Context, message string)`
- Info: `msg.Info(ctx echo.Context, message string)`
- Warning: `msg.Warning(ctx echo.Context, message string)`
- Danger: `msg.Danger(ctx echo.Context, message string)`
The _message_ string can contain HTML.
#### Rendering messages
When a flash message is retrieved from storage in order to be rendered, it is deleted from storage so that it cannot be rendered again.
The `Page` has a method that can be used to fetch messages for a given type from within the template: `Page.GetMessages(typ msg.Type)`. This is used rather than the _funcmap_ because the `Page` contains the request context which is required in order to access the session data. Since the `Page` is the data destined for the templates, you can use: `{{.GetMessages "success"}}` for example.
To make things easier, a template _component_ is already provided, located at `templates/components/messages.gohtml`. This will render all messages of all types simply by using `{{template "messages" .}}` either within your page or layout template.
### Pager
A very basic mechanism is provided to handle and facilitate paging located in `pkg/page/pager.go`. When a `Page` is initialized, so is a `Pager` at `Page.Pager`. If the requested URL contains a `page` query parameter with a numeric value, that will be set as the page number in the pager.
During initialization, the _items per page_ amount will be set to the default, controlled via constant, which has a value of 20. It can be overridden by changing `Pager.ItemsPerPage` but should be done before other values are set in order to not provide incorrect calculations.
Methods include:
- `SetItems(items int)`: Set the total amount of items in the entire result-set
- `IsBeginning()`: Determine if the pager is at the beginning of the pages
- `IsEnd()`: Determine if the pager is at the end of the pages
- `GetOffset()`: Get the offset which can be useful is constructing a paged database query
There is currently no template (yet) to easily render a pager.
### CSRF
By default, all non GET requests will require a CSRF token be provided as a form value. This is provided by middleware and can be adjusted or removed in the router.
The `Page` will contain the CSRF token for the given request. There is a CSRF helper component template which can be used to easily render a hidden form element in your form which will contain the CSRF token and the proper element name. Simply include `{{template "csrf" .}}` within your form.
### Automatic template parsing
Dealing with templates can be quite tedious and annoying so the `Page` aims to make it as simple as possible with the help of the [template renderer](#template-renderer). To start, templates for _pages_ are grouped in the following directories within the `templates` directory:
- `layouts`: Base templates that provide the entire HTML wrapper/layout. This template should include a call to `{{template "content" .}}` to render the content of the `Page`.
- `pages`: Templates that are specific for a given route/page. These must contain `{{define "content"}}{{end}}` which will be injected in to the _layout_ template.
- `components`: A shared library of common components that the layout and base template can leverage.
Specifying which templates to render for a given `Page` is as easy as:
```go
page.Name = "home"
page.Layout = "main"
```
That alone will result in the following templates being parsed and executed when the `Page` is rendered:
1) `layouts/main.gohtml` as the base template
2) `pages/home.gohtml` to provide the `content` template for the layout
3) All template files located within the `components` directory
4) The entire [funcmap](#funcmap)
The [template renderer](#template-renderer) also provides caching and local hot-reloading.
### Cached responses
A `Page` can have cached enabled just by setting `Page.Cache.Enabled` to `true`. The `TemplateRenderer` will automatically handle caching the HTML output, headers and status code. Cached pages are stored using a key that matches the full request URL and [middleware](#cache-middleware) is used to serve it on matching requests.
By default, the cache expiration time will be set according to the configuration value located at `Config.Cache.Expiration.Page` but it can be set per-page at `Page.Cache.Expiration`.
#### Cache tags
You can optionally specify cache tags for the `Page` by setting a slice of strings on `Page.Cache.Tags`. This provides the ability to build in cache invalidation logic in your application driven by events such as entity operations, for example.
You can use the [cache client](#cache) on the `Container` to easily [flush cache tags](#flush-tags), if needed.
#### Cache middleware
Cached pages are served via the middleware `ServeCachedPage()` in the `middleware` package.
The cache is bypassed if the requests meet any of the following criteria:
1) Is not a GET request
2) Is made by an authenticated user
Cached pages are looked up for a key that matches the exact, full URL of the given request.
### Data
The `Data` field on the `Page` is of type `any` and is what allows your route to pass whatever it requires to the templates, alongside the `Page` itself.
### Forms
The `Form` field on the `Page` is similar to the `Data` field, but it's meant to store a struct that represents a form being rendered on the page.
An example of this pattern is:
```go
type ContactForm struct {
Email string `form:"email" validate:"required,email"`
Message string `form:"message" validate:"required"`
form.Submission
}
```
Embedding `form.Submission` satisfies the `form.Form` interface and makes dealing with submissions and validation extremely easy.
Then in your page:
```go
p := page.New(ctx)
p.Form = form.Get[ContactForm](ctx)
```
This will either initialize a new form to be rendered, or load one previously stored in the context (ie, if it was already submitted). How the _form_ gets populated with values so that your template can render them is covered in the next section.
#### Submission processing
Form submission processing is made extremely simple by leveraging functionality provided by [Echo binding](https://echo.labstack.com/guide/binding/), [validator](https://github.com/go-playground/validator) and the `Submission` struct located in `pkg/form/submission.go`.
Using the example form above, this is all you would have to do within the _POST_ callback for your route:
Start by submitting the form along with the request context. This will:
1. Store a pointer to the form so that your _GET_ callback can access the form values (shown previously). That allows the form to easily be re-rendered with any validation errors it may have as well as the values that were provided.
2. Parse the input in the _POST_ data to map to the struct so the fields becomes populated. This uses the `form` struct tags to map form input values to the struct fields.
3. Validate the values in the struct fields according to the rules provided in the optional `validate` struct tags.
```go
var input ContactForm
err := form.Submit(ctx, &input)
```
Check the error returned, and act accordingly. For example:
```go
switch err.(type) {
case nil:
// All good!
case validator.ValidationErrors:
// The form input was not valid, so re-render the form
return c.Page(ctx)
default:
// Request failed, show the error page
return err
}
```
And finally, your template:
```html
```
Second, render the error messages, if there are any for a given field:
```go
{{template "field-errors" (.Form.GetFieldErrors "Email")}}
```
### Headers
HTTP headers can be set either via the `Page` or the _context_:
```go
p := page.New(ctx)
p.Headers["HeaderName"] = "header-value"
```
```go
ctx.Response().Header().Set("HeaderName", "header-value")
```
### Status code
The HTTP response status code can be set either via the `Page` or the _context_:
```go
p := page.New(ctx)
p.StatusCode = http.StatusTooManyRequests
```
```go
ctx.Response().Status = http.StatusTooManyRequests
```
### Metatags
The `Page` provides the ability to set basic HTML metatags which can be especially useful if your web application is publicly accessible. Only fields for the _description_ and _keywords_ are provided but adding additional fields is very easy.
```go
p := page.New(ctx)
p.Metatags.Description = "The page description."
p.Metatags.Keywords = []string{"Go", "Software"}
```
A _component_ template is included to render metatags in `core.gohtml` which can be used by adding `{{template "metatags" .}}` to your _layout_.
### URL and link generation
Generating URLs in the templates is made easy if you follow the [routing patterns](#patterns) and provide names for your routes. Echo provides a `Reverse` function to generate a route URL with a given route name and optional parameters. This function is made accessible to the templates via _funcmap_ function `url`.
As an example, if you have route such as:
```go
e.GET("/user/profile/:user", handler.Get).Name = "user_profile"
```
And you want to generate a URL in the template, you can:
```go
{{url "user_profile" 1}
```
Which will generate: `/user/profile/1`
There is also a helper function provided in the [funcmap](#funcmap) to generate links which has the benefit of adding an _active_ class if the link URL matches the current path. This is especially useful for navigation menus.
```go
{{link (url "user_profile" .AuthUser.ID) "Profile" .Path "extra-class"}}
```
Will generate:
```html
```
Assuming the current _path_ is `/user/profile/1`; otherwise the `is-active` class will be excluded.
### HTMX support
[HTMX](https://htmx.org/) is an awesome JavaScript library allows you to access AJAX, CSS Transitions, WebSockets and Server Sent Events directly in HTML, using attributes, so you can build modern user interfaces with the simplicity and power of hypertext.
Many examples of its usage are available in the included examples:
- All navigation links use [boost](https://htmx.org/docs/#boosting) which dynamically replaces the page content with an AJAX request, providing a SPA-like experience.
- All forms use either [boost](https://htmx.org/docs/#boosting) or [hx-post](https://htmx.org/docs/#triggers) to submit via AJAX.
- The mock search autocomplete modal uses [hx-get](https://htmx.org/docs/#targets) to fetch search results from the server via AJAX and update the UI.
- The mock posts on the homepage/dashboard use [hx-get](https://htmx.org/docs/#targets) to fetch and page posts via AJAX.
All of this can be easily accomplished without writing any JavaScript at all.
Another benefit of [HTMX](https://htmx.org/) is that it's completely backend-agnostic and does not require any special tools or integrations on the backend. But to make things easier, included is a small package to read and write [HTTP headers](https://htmx.org/docs/#requests) that HTMX uses to communicate additional information and commands.
The `htmx` package contains the headers for the _request_ and _response_. When a `Page` is initialized, `Page.HTMX.Request` will also be initialized and populated with the headers that HTMX provides, if HTMX made the request. This allows you to determine if HTMX is making the given request and what exactly it is doing, which could be useful both in your _route_ as well as your _templates_.
If you need to set any HTMX headers in your `Page` response, this can be done by altering `Page.HTMX.Response`.
#### Layout template override
To facilitate easy partial rendering for HTMX requests, the `Page` will automatically change your _Layout_ template to use `htmx.gohtml`, which currently only renders `{{template "content" .}}`. This allows you to use an HTMX request to only update the content portion of the page, rather than the entire HTML.
This override only happens if the HTMX request being made is **not a boost** request because **boost** requests replace the entire `body` element so there is no need to do a partial render.
#### Conditional processing / rendering
Since HTMX communicates what it is doing with the server, you can use the request headers to conditionally process in your _route_ or render in your _template_, if needed. If your routes aren't doing multiple things, you may not need this, but it's worth knowing how flexible you can be.
A simple example of this:
```go
if page.HTMX.Request.Target == "search" {
// You know this request HTMX is fetching content just for the #search element
}
```
```go
{{if eq .HTMX.Request.Target "search"}}
// Render content for the #search element
{{end}}
```
#### CSRF token
If [CSRF](#csrf) protection is enabled, the token value will automatically be passed to HTMX to be included in all non-GET requests. This is done in the `footer` template by leveraging HTMX [events](https://htmx.org/reference/#events).
### Rendering the page
Once your `Page` is fully built, rendering it via the embedded `TemplateRenderer` in your _handler_ can be done simply by calling `RenderPage()`:
```go
func (c *home) Get(ctx echo.Context) error {
p := page.New(ctx)
p.Layout = templates.LayoutMain
p.Name = templates.PageHome
return c.RenderPage(ctx, p)
}
```
## Template renderer
The _template renderer_ is a _Service_ on the `Container` that aims to make template parsing and rendering easy and flexible. It is the mechanism that allows the `Page` to do [automatic template parsing](#automatic-template-parsing). The standard `html/template` is still the engine used behind the scenes. The code can be found in `pkg/services/template_renderer.go`.
Here is an example of a complex rendering that uses multiple template files as well as an entire directory of template files:
```go
buf, err = c.TemplateRenderer.
Parse().
Group("page").
Key("home").
Base("main").
Files("layouts/main", "pages/home").
Directories("components").
Execute(data)
```
This will do the following:
- [Cache](#caching) the parsed template with a _group_ of `page` and _key_ of `home` so this parse only happens once
- Set the _base template file_ as `main`
- Include the templates `templates/layout/main.gohtml` and `templates/pages/home.gohtml`
- Include all templates located within the directory `templates/components`
- Include the [funcmap](#funcmap)
- Execute the parsed template with `data` being passed in to the templates
Using the example from the [page rendering](#rendering-the-page), this is will execute:
```go
buf, err = c.TemplateRenderer.
Parse().
Group("page").
Key(page.Name).
Base(page.Layout).
Files(
fmt.Sprintf("layouts/%s", page.Layout),
fmt.Sprintf("pages/%s", page.Name),
).
Directories("components").
Execute(page)
```
If you have a need to _separately_ parse and cache the templates then later execute, you can separate the operations:
```go
_, err := c.TemplateRenderer.
Parse().
Group("my-group").
Key("my-key").
Base("auth").
Files("layouts/auth", "pages/login").
Directories("components").
Store()
```
```go
tpl, err := c.TemplateRenderer.Load("my-group", "my-key")
buf, err := tpl.Execute(data)
```
### Custom functions
All templates will be parsed with the [funcmap](#funcmap) so all of your custom functions as well as the functions provided by [sprig](https://github.com/Masterminds/sprig) will be available.
### Caching
Parsed templates will be cached within a `sync.Map` so the operation will only happen once per cache _group_ and _ID_. Be careful with your cache _group_ and _ID_ parameters to avoid collisions.
### Hot-reload for development
If the current [environment](#environments) is set to `config.EnvLocal`, which is the default, the cache will be bypassed and templates will be parsed every time they are requested. This allows you to have hot-reloading without having to restart the application so you can see your HTML changes in the browser immediately.
### File configuration
To make things easier and less repetitive, parameters given to the _template renderer_ must not include the `templates` directory or the template file extensions. The file extension is stored as a constant (`TemplateExt`) within the `config` package.
## Funcmap
The `funcmap` package provides a _function map_ (`template.FuncMap`) which will be included for all templates rendered with the [template renderer](#template-renderer). Aside from a few custom functions, [sprig](https://github.com/Masterminds/sprig) is included which provides over 100 commonly used template functions. The full list is available [here](http://masterminds.github.io/sprig/).
To include additional custom functions, add to the map in `NewFuncMap()` and define the function in the package. It will then become automatically available in all templates.
## Cache
As previously mentioned, the default cache implementation is a simple in-memory store, backed by [otter](https://github.com/maypok86/otter), a lockless cache that uses [S3-FIFO](https://s3fifo.com/) eviction. The `Container` houses a `CacheClient` which is a useful, wrapper to interact with the cache (see examples below). Within the `CacheClient` is the underlying store interface `CacheStore`. If you wish to use a different store, such as Redis, and want to keep using the `CacheClient`, simply implement the `CacheStore` interface with a Redis library and adjust the `Container` initialization to use that.
The built-in usage of the cache is currently only for optional [page caching](#cached-responses) and a simple example route located at `/cache` where you can set and view the value of a given cache entry.
Since the current cache is in-memory, there's no need to adjust the `Container` during tests. When this project used Redis, the configuration had a separate database that would be used strictly for tests to avoid writing to your primary database. If you need that functionality, it is easy to add back in.
### Set data
**Set data with just a key:**
```go
err := c.Cache.
Set().
Key("my-key").
Data(myData).
Expiration(time.Hour * 2).
Save(ctx)
```
**Set data within a group:**
```go
err := c.Cache.
Set().
Group("my-group").
Key("my-key").
Expiration(time.Hour * 2).
Data(myData).
Save(ctx)
```
**Include cache tags:**
```go
err := c.Cache.
Set().
Key("my-key").
Tags("tag1", "tag2").
Expiration(time.Hour * 2).
Data(myData).
Save(ctx)
```
### Get data
```go
data, err := c.Cache.
Get().
Group("my-group").
Key("my-key").
Fetch(ctx)
```
### Flush data
```go
err := c.Cache.
Flush().
Group("my-group").
Key("my-key").
Execute(ctx)
```
### Flush tags
This will flush all cache entries that were tagged with the given tags.
```go
err := c.Cache.
Flush().
Tags("tag1", "tag2").
Execute(ctx)
```
### Tagging
As shown in the previous examples, cache tags were provided because they can be convenient. However, maintaining them comes at a cost and it may not be a good fit for your application depending on your needs. When including tags, the `CacheClient` must lock in order to keep the tag index in sync. And since the tag index cannot support eviction, since that could result in a flush call not actually flushing the tag's keys, the maps that provide the index do not have a size limit. See the code for more details.
## Tasks
Tasks are queued operations to be executed in the background, either immediately, at a specfic time, or after a given amount of time has passed. Some examples of tasks could be long-running operations, bulk processing, cleanup, notifications, etc.
Since we're already using [SQLite](https://sqlite.org/) for our database, it's available to act as a persistent store for queued tasks so that tasks are never lost, can be retried until successful, and their concurrent execution can be managed. [Backlite](https://github.com/mikestefanello/backlite) is the library chosen to interface with [SQLite](https://sqlite.org/) and handle queueing tasks and processing them asynchronously.
To make things easy, the _Backlite_ client (`TaskClient`) is provided as a _Service_ on the `Container` which allows you to register queues and add tasks.
### Queues
A full example of a queue implementation can be found in `pkg/tasks` with an interactive form to create a task and add to the queue at `/task` (see `pkg/handlers/task.go`). Also refer to the [Backlite](https://github.com/mikestefanello/backlite) documentation for reference and examples.
See `pkg/tasks/register.go` for a simple way to register all of your queues and to easily pass the `Container` to them so the queue processor callbacks have access to all of your app's dependencies.
### Dispatcher
The _task dispatcher_ is what manages the worker pool used for executing tasks in the background. It monitors incoming and scheduled tasks and handles sending them to the pool for execution by the queue's processor callback. This must be started in order for this to happen. In `cmd/web/main.go`, the _task dispatcher_ is automatically started when the app starts via:
```go
c.Tasks.Start(ctx)
```
The app [configuration](#configuration) contains values to configure the client and dispatcher including how many goroutines to use, when to release stuck tasks back into the queue, and how often to cleanup retained tasks in the database.
When the app is shutdown, the dispatcher is given 10 seconds to wait for any in-progress tasks to finish execution. This can be changed in `cmd/web/main.go`.
## Cron
By default, no cron solution is provided because it's very easy to add yourself if you need this. You can either use a [ticker](https://pkg.go.dev/time#Ticker) or a [library](https://github.com/robfig/cron).
## Static files
Static files are currently configured in the router (`pkg/handler/router.go`) to be served from the `static` directory. If you wish to change the directory, alter the constant `config.StaticDir`. The URL prefix for static files is `/files` which is controlled via the `config.StaticPrefix` constant.
### Cache control headers
Static files are grouped separately so you can apply middleware only to them. Included is a custom middleware to set cache control headers (`middleware.CacheControl`) which has been added to the static files router group.
The cache max-life is controlled by the configuration at `Config.Cache.Expiration.StaticFile` and defaults to 6 months.
### Cache-buster
While it's ideal to use cache control headers on your static files so browsers cache the files, you need a way to bust the cache in case the files are changed. In order to do this, a function is provided in the [funcmap](#funcmap) to generate a static file URL for a given file that appends a cache-buster query. This query string is randomly generated and persisted until the application restarts.
For example, to render a file located in `static/picture.png`, you would use:
```html
```
Which would result in:
```html
```
Where `9fhe73kaf3` is the randomly-generated cache-buster.
## Email
An email client was added as a _Service_ to the `Container` but it is just a skeleton without any actual email-sending functionality. The reason is because there are a lot of ways to send email and most prefer using a SaaS solution for that. That makes it difficult to provide a generic solution that will work for most applications.
The structure in the client (`MailClient`) makes composing emails very easy and you have the option to construct the body using either a simple string or with a template by leveraging the [template renderer](#template-renderer). The standard library can be used if you wish to send email via SMTP and most SaaS providers have a Go package that can be used if you choose to go that direction. **You must** finish the implementation of `MailClient.send`.
The _from_ address will default to the configuration value at `Config.Mail.FromAddress`. This can be overridden per-email by calling `From()` on the email and passing in the desired address.
See below for examples on how to use the client to compose emails.
**Sending with a string body**:
```go
err = c.Mail.
Compose().
To("hello@example.com").
Subject("Welcome!").
Body("Thank you for registering.").
Send(ctx)
```
**Sending with a template body**:
```go
err = c.Mail.
Compose().
To("hello@example.com").
Subject("Welcome!").
Template("welcome").
TemplateData(templateData).
Send(ctx)
```
This will use the template located at `templates/emails/welcome.gohtml` and pass `templateData` to it.
## HTTPS
By default, the application will not use HTTPS but it can be enabled easily. Just alter the following configuration:
- `Config.HTTP.TLS.Enabled`: `true`
- `Config.HTTP.TLS.Certificate`: Full path to the certificate file
- `Config.HTTP.TLS.Key`: Full path to the key file
To use _Let's Encrypt_ follow [this guide](https://echo.labstack.com/cookbook/auto-tls/#server).
## Logging
By default, the [Echo logger](https://echo.labstack.com/guide/customization/#logging) is not used for the following reasons:
1) It does not support structured logging, which makes it difficult to deal with variables, especially if you intend to store a logger in context with pre-populated attributes.
2) The upcoming v5 release of Echo will not contain a logger.
3) It should be easy to use whatever logger you prefer (even if that is Echo's logger).
The provided implementation uses the relatively new [log/slog](https://go.dev/blog/slog) library which was added to Go in version 1.21 but swapping that out for whichever you prefer is very easy.
### Context
The simple `pkg/log` package provides the ability to set and get a logger from the Echo context. This is especially useful when you use the provided logger middleware (see below). If you intend to use a different logger, modify these methods to receive and return the logger of your choice.
### Usage
Adding a logger to the context:
```go
logger := slog.New(logHandler).With("id", requestId)
log.Set(ctx, logger)
```
Access and use the logger:
```go
func (h *handler) Page(ctx echo.Context) error {
log.Ctx(ctx).Info("send a message to the log",
"value_one", valueOne,
"value_two", valueTwo,
)
}
```
### Log level
When the _Container_ configuration is initialized (`initConfig()`), the `slog` default log level is set based on the environment. `INFO` is used for production and `DEBUG` for everything else.
### Middleware
The `SetLogger()` middleware has been added to the router which sets an initialized logger on the request context. It's recommended that this remains after Echo's `RequestID()` middleware because it will add the request ID to the logger which means that all logs produced for that given request will contain the same ID, so they can be linked together. If you want to include more attributes on all request logs, set those fields here.
The `LogRequest()` middleware is a replacement for Echo's `Logger()` middleware which produces a log of every request made, but uses our logger rather than Echo's.
```
2024/06/15 09:07:11 INFO GET /contact request_id=gNblvugTKcyLnBYPMPTwMPEqDOioVLKp ip=::1 host=localhost:8000 referer="" status=200 bytes_in=0 bytes_out=5925 latency=107.527803ms
```
## Roadmap
Future work includes but is not limited to:
- Flexible pager templates
- Expanded HTMX examples and integration
- Admin section
## Credits
Thank you to all of the following amazing projects for making this possible.
- [alpinejs](https://github.com/alpinejs/alpine)
- [backlite](https://github.com/mikestefanello/backlite)
- [bulma](https://github.com/jgthms/bulma)
- [echo](https://github.com/labstack/echo)
- [golang-migrate](https://github.com/golang-migrate/migrate)
- [go](https://go.dev/)
- [go-sqlite3](https://github.com/mattn/go-sqlite3)
- [goquery](https://github.com/PuerkitoBio/goquery)
- [htmx](https://github.com/bigskysoftware/htmx)
- [jwt](https://github.com/golang-jwt/jwt)
- [otter](https://github.com/maypok86/otter)
- [sessions](https://github.com/gorilla/sessions)
- [sprig](https://github.com/Masterminds/sprig)
- [sqlite](https://sqlite.org/)
- [testify](https://github.com/stretchr/testify)
- [validator](https://github.com/go-playground/validator)
- [viper](https://github.com/spf13/viper)
## Similar Projects
- [go-templ-htmx-templ](https://github.com/HoneySinghDev/go-templ-htmx-template)
- [go-webly](https://github.com/gowebly/gowebly)