Deno-Spring

Deno-Spring is a compact, high-performance and full-featured web server framework based on Deno. It can be developed quickly using annotations(decorators) like Java SpringBoot framework.

Shortcut mode

Create a mod.ts file and write the following content, then run deno run --allow-all mod.ts.

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

@Bootstrap
export default class {
    constructor(app: Server) {
        app.get("/:id", (ctx) => {
            return "hello " + ctx.params.id;
        });
    }
}

Visit http://localhost:3000/jack, hello jack will be returned.

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

Decorator mode

Decorator mode and shortcut 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.

In decorator mode, you must first create a configuration file named “deno.jsonc” in the project root with the following content:

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
  }
}

Then modify the content of mod.ts as follows, in order to inject all components with decorators into the application by app.modules method.

@Bootstrap
export default class {
    constructor(app: Server) {
        app.modules(Authenticator, ErrorController, UserController, UserService);
    }
}

1. Interceptor

The interceptor is not required, but if there is one, the methods in it will be executed in order. If the interceptor method returns true, it means that the interception is successful and other methods and routes will no longer be executed.

// Authenticator.ts
@Interceptor
export class Authenticator {
    cors(ctx: Context): boolean {
        // do something first
        return true;
    }
    auth(ctx: Context): boolean {
        // do something second
        return false;
    }
}

2. ErrorHandler

If an error handler component is defined, all errors within the framework will be handled by it.

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

3. Controller

Create a routing controller and inject a service class.

// UserController.ts
@Controller("/prefix")
export class UserController {
    @Autowired
    userService!: UserService;

    @Get("/:id")
    getUser(ctx: Context) {
        return this.userService.getUser(ctx.params.id);
    }
}

Note that if you want to use the service class in the constructor, you need to refer to the following usage:

// UserController.ts
@Controller("/prefix")
export class UserController {
    constructor(public userService: UserService) {
        this.userService.init();
    }

    @Get("/:id")
    getUser(ctx: Context) {
        return this.userService.getUser(ctx.params.id);
    }
}

4. Component

// UserService.ts
@Component
export class UserService {
    getUser(id: string) {
        // do something
    }
}

5. View

View decorator 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. First you can set the template root directory in the startup class.

// mod.ts
@Bootstrap
export default class {
    constructor(app: Server) {
        app.views("./views");  // Add template root directory
        app.modules(Authenticator, ErrorController, UserController, UserService);
    }
}

// UserController.ts
@Controller("/prefix")
export class UserController {
    @Autowired
    userService!: UserService;

    @Get("/:id")
    @View("index.html") // or @View("./project/path/index.html") if the root directory is not set
    getUser(ctx: Context) {
        return this.userService.getUser(ctx.params.id);
    }
}

// index.html
// Assume that the user object is { name, age }
<h1>Hello, {{= name }}, Your age is {{= age }}</h1>

6. Attribute

If you want to use global properties or methods in the template, you can define an attribute decorator. The method name is the attribute name.

// Attributes.ts
@Component
export class Attributes {
    @Attribute
    appName() {
        return "spring";
    }
}

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

API Reference

app: Server

• app.port HTTP server listening port, default 3000.
• app.hostname HTTP server hostname, default “0.0.0.0”
• app.views The root of template files, default “”
• app.assets The paths of static resources
• app.modules Load classes that need to use decorator in the application
• app.get, app.post, app.put… Request methods with (path, handler) parameters

Decorators

Context

Context is an instance passed to controllers, Interceptors 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 307.

Utils

• ctx.serve(staticFile) Handle static resources and return ArrayBuffer
• ctx.render(tmplText, data) Render template text, usually not needed.
• 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.

Return types

Controller methods are allowed to return the following object types:

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

Built-in template engine syntax

The built-in template engine refers to doT and EasyTemplateJS. It can be used as a independency feature.

• {{= }} Interpolation.

• {{ }} Evaluate code snippet in javascript. Note that the variables do not need to be declared.

{{ result = 60*60; }}
<div>{{= result }}</div>

• {{? }} {{?? }} {{? }} Conditional statement.

{{? gender == 0 }}
  <div>Female</div>
{{?? gender == 1 }}
  <div>Male</div>
{{?? }}
  <div>Unknown</div>
{{? }}

• {{~ }} {{~ }} Iterative statement.

<ul>
{{~ users:user:index }}
  <li>{{= index+1 }} - {{= user.name }}<li>
{{~ }}
</ul>

• {{> }} Block placeholder.
• {{< }} Block content definition.

The above two syntaxes can belong to two different files and only need to be included.

{{> content }}

{{< content }}
  <h1>Hello spring.</h1>
{{< }}

• {{@ }} Partial including in layout mode. You must be rendered by view(file, data) method.

// header.html
<h1>Hello spring.</h1>

// index.html
{{@ header.html }}

Methods

• init(templateRoot: string) Initialize custom options（not necessary). relative to the project root, default “”
• import(attribute: object) Custom global properties or functions, default {}
• compile(tmpl) Compile the specify template text to a function.
• render(tmpl, data) Compile and render the template with data.
• view(file, data) Render the template file with data (using cache).

Reserved symbols

• {{! }}
• {{# }}
• {{$ }}
• {{% }}
• {{^ }}
• {{& }}
• {{+ }}
• {{- }}
• {{* }}