Deno-Spring

A compact, high-performance and full-featured web server framework in Deno.

Shortcut mode

import { app } from "https://deno.land/x/spring/mod.ts";

app.get("/:user", (ctx) => ctx.params.user);
app.boot();

Note that features such as plugins, middlewares, template engine and unified error handling cannot be used in shortcut mode, you must solve them in other ways.

Decorator mode

Importing a ts file containing any decorators to use its features. Shortcut mode and decorator mode do not conflict and can be used together. The only difference in performance between the two is that the latter needs to parse all decorators at startup, it is almost the same in runtime.

// mod.ts
import app from "https://deno.land/x/spring/mod.ts";
import "./controllers/MyController.ts"; // DO NOT forget import the controllers

app.boot();

1. Controllers

// MyController.ts
import { Context, Controller, Get } from "https://deno.land/x/spring/mod.ts";

@Controller("/prefix")
export class MyController {
  @Get("/:user")
  getUser(ctx: Context) {
    return ctx.params.user;
  }
}

2. Middlewares

You can add middleware decorator on any class method, including controllers. The role of the middleware parameter is to set the execution priority.

// MyMiddleware.ts
import { Context, Middleware } from "https://deno.land/x/spring/mod.ts";

export class MyMiddleware {
  @Middleware(2)
  cors(ctx: Context) {
    // do something second
  }

  @Middleware(1)
  auth(ctx: Context) {
    // do something first
  }
}

3. Plugins

Plugin decorators can only be added to classes, and the parameter is the name bound to the context.

// MyPlugin.ts
import { Plugin } from "https://deno.land/x/spring/mod.ts";

@Plugin("redis")
export class Redis {
  constructor() {
    // connect to redis server and create a client
  }
  get(key) {
    // do something
  }
  set(key, value) {
    // do something
  }
}

Then you can use redis object as singleton instance in any controllers with ctx.redis.

4. View

View decorators are used to decorate controller methods, and its parameter is the template file path. After adding it the built-in template engine will be used for rendering automatically. The built-in engine syntax see SYNTAX.md

// mod.ts
app.boot({  // Engine options, not necessary
  viewRoot: "./pages",   // The root of template files
  imports: {  // Global imports for template
    siteName: "My Blog"
  }
});

// controller.ts
import { Context, Controller, Get, View } from "https://deno.land/x/spring/mod.ts";

@Controller("/prefix")
export class MyController {
  @Get("/:user")
  @View("index.html") // or @View("./project/path/index.html") if options not initialized
  getUser(ctx: Context) {
    return { name: ctx.params.user };
  }
}

// index.html
<h1>Hello, {{= name }}</h1>

5. ErrorHandler

If an error handler decorator is defined, all errors within the framework will be handled by it. Like middleware, you can define it in any class method but only once. This decorator has no parameters.

// error.ts
import { Context, ErrorHandler } from "https://deno.land/x/spring/mod.ts";

export class AnyClass {
  @ErrorHandler()
  error(ctx: Context, err: Error) {
    return {
      status: ctx.status,
      message: err.message,
    };
  }
}

API Reference

Bootstrap

To start the web server, you simply write a single line of code app.boot(). The options as follow:

• port HTTP server listening port, default 3000.
• hostname HTTP server hostname, default “0.0.0.0”
• viewRoot The root of template files
• imports Global imports for template
• assets The array of paths of static resources
• onListen
• onError

Routes

The route methods including get,post,put,del,patch,head,opt, and all methods have the same parameters.

• path Route path.
• handler Request handle function.

Decorators

Context

Context is an instance passed to controllers, middlewares and error handler, it contains properties and methods related to requests and responses.

Request Properties

• ctx.params The parameters on route path
• ctx.query The parameters on query string
• ctx.url ex. https://example.com:3000/users?page=1
• ctx.origin ex. https://example.com:3000
• ctx.protocol ex. https:
• ctx.host ex. example.com:3000
• ctx.hostname ex. example.com
• ctx.port ex. 3000
• ctx.path ex. /users
• ctx.method Standard http request methods
• ctx.has, ctx.get Shortcuts for obtain reqeust headers. Refer to https://deno.com/deploy/docs/runtime-headers
• ctx.cookies Including one method to get request cookie: ctx.cookies.get(name)
• ctx.text, ctx.json, ctx.form, ctx.blob, ctx.buffer Promised methods to parse request body.

Response Properties

• ctx.status
• ctx.status=
• ctx.statusText
• ctx.statusText=
• ctx.cookies Including two methods to operate response cookie: set(name, value),delete(name)

Response Methods

• ctx.set(name, value) The following 3 methods are used to manipulate response headers
• ctx.redirect(url[, status]) Redirect url with default status code 308.

Others

• ctx.view(tmplFile, data) If the controller method does not add a @View decorator, you can call this method to return the rendered text content.
• ctx.render(tmplText, data) Render template text, usually not needed.

Return types

Controller methods are allowed to return the following object types:

• BodyInit: Blob, BufferSource, FormData, ReadableStream, URLSearchParams, or USVString
• Response: Native response instance.