# HTTP Handlers {% hint style="info" %} Please see [Mandarine MVC Controllers](https://mandarineframework.gitbook.io/mandarine-ts/mandarine-mvc/web-mvc/controllers) before continuing. {% endhint %} ## How to properly use HTTP Handlers HTTP handlers as we have mentioned before, are just methods that are decorated with [route decoration](https://mandarineframework.gitbook.io/mandarine-ts/mandarine-mvc/web-mvc/controllers/using-routes-and-http-handlers#usage). Although, they can handle complex operations by using *HTTP Parameter decorators.* ### HTTP Parameter Decorators They are decorators that are used in the parameters of a HTTP Handler. Every decorator provides a different functionality, but the objective is the same for all of them: The interaction of the current request & your mandarine-powered web application. * `@RouteParam(name?: string)` * It will bring the value of the param declared on the route path. This value comes from the client's request. * `name` is used to identify what parameter from the route path we are trying to get * Optional * If name is ignored, then its value will be the parameter's key. * `@QueryParam(name?: string)` * It will bring the value of the desired query parameter. This value comes from the URL a client has requested. * `name` is used to identify what query parameter from the request's url we are trying to get * Optional * If name is ignored, then its value will be the parameter's key. * `@RequestBody()` * It will bring the value from request's body. * It is the equivalent to [request.body()](https://doc.deno.land/https/raw.githubusercontent.com/oakserver/oak/master/request.ts#Request). * Mandarine will try to parse it when the content type of the body is **application/x-www-form-urlencoded** or **application/json** . If the content-type is not known, the whole body object will be inject it instead. * `@Session()` * It will bring the current session object located in the request. * `@Cookie(name?: string)` * It will bring the cookie with the key `name` * `name` is used to identify what cookie from the request we are trying to get * Optional * If name is ignored, then its value will be the parameter's key. * `@ServerRequestParam()` * It will bring the all the information available from the request made by a client. * The result is a [ServerRequest](https://doc.deno.land/https/raw.githubusercontent.com/denoland/deno/master/std/http/server.ts#ServerRequest) object * `@RequestParam()` * It will bring the all the information available from the request made by a client. * The result is a [Request](https://doc.deno.land/https/raw.githubusercontent.com/oakserver/oak/master/request.ts#Request) object from *Oak.* * `@ResponseParam()` * It will bring the value from the current response given by the server before being delivered to the client. * Modifications to the request can and will affect the outcome of the response delivered to the client after the HTTP handler has been executed. * `@Model()` * It will inject the [ViewModel](https://doc.deno.land/https/raw.githubusercontent.com/mandarineorg/mandarinets/master/mvc-framework/core/modules/view-engine/viewModel.ts) object, used to create data models for templates. (More information [here](https://mandarineframework.gitbook.io/mandarine-ts/mandarine-mvc/template-engine/accessing-data-from-template)) ## Usage {% tabs %} {% tab title="@RouteParam" %} ```typescript import { Controller, GET, RouteParam, MandarineCore } from "https://deno.land/x/mandarinets/mod.ts"; @Controller('/api') export class Foo { @GET('/say-hi/:personsName') public httpHandler1(@RouteParam() personsName: string): string { return `Hello ${personsName}, welcome to Mandarine.TS`; } // This one specifies manually what parameter we are trying to get @GET('/say-hello/:name') public httpHandler2(@RouteParam('name') personsName: string): string { return `Hello ${personsName}, welcome to Mandarine.TS`; } } new MandarineCore().MVC().run(); ``` Request ``` # http://localhost:8080/api/say-hi/Bill Hello Bill, Welcome to Mandarine.TS # http://localhost:8080/api/say-hello/Mark Hello Mark, Welcome to Mandarine.TS ``` {% endtab %} {% tab title="@QueryParam" %} ```typescript import { Controller, GET, QueryParam, MandarineCore } from "https://deno.land/x/mandarinets/mod.ts"; @Controller('/api') export class Foo { @GET('/say-hi') public httpHandler1(@QueryParam() personsName: string): string { return `Hello ${personsName}, welcome to Mandarine.TS`; } // This one specifies manually what query parameter we are trying to get @GET('/say-hello') public httpHandler2(@QueryParam('name') personsName: string): string { return `Hello ${personsName}, welcome to Mandarine.TS`; } } new MandarineCore().MVC().run(); ``` Result ``` # http://localhost:8080/say-hi?personsName=Will Hello Will, welcome to Mandarine.TS # http://localhost:8080/say-hello?name=Cristopher Hello Cristopher, welcome to Mandarine.TS ``` {% endtab %} {% tab title="@RequestBody" %} ```typescript import { Controller, POST, QueryParam, MandarineCore } from "https://deno.land/x/mandarinets/mod.ts"; interface UserData { id: number; username: string; } @Controller('/api') export class Foo { @POST('/add-user-json') public handler(@RequestBody() data: UserData) { return `User with Id ${data.id} and Username ${data.username} has been added`; } @POST('/add-user-form-url-encoded') public handler(@RequestBody() data: UserData) { return `User with Id ${data['id']} and Username ${data['username']} has been added`; } } new MandarineCore().MVC().run(); ``` Result ``` # POST /add-user-json HTTP/1.1 # Host: 127.0.0.1:8080 # Content-Type: application/json # { "name": "Andres", "id": 1 } User with Id 1 and Username Andres has been added # POST /add-user-form-url-encoded HTTP/1.1 # Host: 127.0.0.1:8080 # Content-Type: application/x-www-form-urlencoded # name=Leonard&id=2 User with Id 2 and Username Leonard has been added ``` {% endtab %} {% tab title="@Session" %} ```typescript import { Controller, GET, Session, MandarineCore } from "https://deno.land/x/mandarinets/mod.ts"; @Controller() export class Foo { @GET('/session-counter') public helloWorld(@Session() session: any): string { if(session.times == undefined) session.times = 0; else session.times = session.times + 1; return `Times = ${session.times}`; } } new MandarineCore().MVC().run(); ``` Result ``` # http://localhost:8080/session-counter Times 0 # http://localhost:8080/session-counter Times 1 # http://localhost:8080/session-counter Times 2 ....... ``` {% endtab %} {% endtabs %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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