by Alex Edwards

[译]Go HTTTP Response代码片段

目录 [−]

  1. 只发送header
  2. 返回普通文本
  3. 返回JSON数据
  4. 返回XML数据
  5. 文件服务
  6. 使用HTML模版
  7. 使用HTML模板生成字符串
  8. 使用嵌套的模版

原文: HTTP Response Snippets for Go by Alex Edwards.

受 Rails layouts and rendering启发, 我觉得写一个关于Go HTTP Response的代码片段集合是一个不错的主意， 它可以用来说明Go web应用程序中通用的HTTP Response的使用。

只发送header

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package main

import (
  "net/http"
)

func main() {
  http.HandleFunc("/", foo)
  http.ListenAndServe(":3000", nil)
}

func foo(w http.ResponseWriter, r *http.Request) {
  w.Header().Set("Server", "A Go Web Server")
  w.WriteHeader(200)
}

测试：

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$ curl -i localhost:3000
HTTP/1.1 200 OK
Server: A Go Web Server
Content-Type: text/plain; charset=utf-8
Content-Length: 0

返回普通文本

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package main

import (
  "net/http"
)

func main() {
  http.HandleFunc("/", foo)
  http.ListenAndServe(":3000", nil)
}

func foo(w http.ResponseWriter, r *http.Request) {
  w.Write([]byte("OK"))
}

测试:

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$ curl -i localhost:3000
HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Content-Length: 2

OK

返回JSON数据

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package main

import (
  "encoding/json"
  "net/http"
)

type Profile struct {
  Name    string
  Hobbies []string
}

func main() {
  http.HandleFunc("/", foo)
  http.ListenAndServe(":3000", nil)
}

func foo(w http.ResponseWriter, r *http.Request) {
  profile := Profile{"Alex", []string{"snowboarding", "programming"}}

  js, err := json.Marshal(profile)
  if err != nil {
    http.Error(w, err.Error(), http.StatusInternalServerError)
    return
  }

  w.Header().Set("Content-Type", "application/json")
  w.Write(js)
}

测试:

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$ curl -i localhost:3000
HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: 56

{"Name":"Alex",Hobbies":["snowboarding","programming"]}

返回XML数据

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package main

import (
  "encoding/xml"
  "net/http"
)

type Profile struct {
  Name    string
  Hobbies []string `xml:"Hobbies>Hobby"`
}

func main() {
  http.HandleFunc("/", foo)
  http.ListenAndServe(":3000", nil)
}

func foo(w http.ResponseWriter, r *http.Request) {
  profile := Profile{"Alex", []string{"snowboarding", "programming"}}

  x, err := xml.MarshalIndent(profile, "", "  ")
  if err != nil {
    http.Error(w, err.Error(), http.StatusInternalServerError)
    return
  }

  w.Header().Set("Content-Type", "application/xml")
  w.Write(x)
}

测试:

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$ curl -i localhost:3000
HTTP/1.1 200 OK
Content-Type: application/xml
Content-Length: 128

<Profile>
  <Name>Alex</Name>
  <Hobbies>
    <Hobby>snowboarding</Hobby>
    <Hobby>programming</Hobby>
  </Hobbies>
</Profile>

文件服务

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package main

import (
  "net/http"
  "path"
)

func main() {
  http.HandleFunc("/", foo)
  http.ListenAndServe(":3000", nil)
}

func foo(w http.ResponseWriter, r *http.Request) {
  // Assuming you want to serve a photo at 'images/foo.png'
  fp := path.Join("images", "foo.png")
  http.ServeFile(w, r, fp)
}

测试:

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$ curl -I localhost:3000
HTTP/1.1 200 OK
Accept-Ranges: bytes
Content-Length: 236717
Content-Type: image/png
Last-Modified: Thu, 10 Oct 2013 22:23:26 GMT

使用HTML模版

模板文件：templates/index.html

templates/index.html
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<h1>Hello { { .Name } }</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>
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package main

import (
  "html/template"
  "net/http"
  "path"
)

type Profile struct {
  Name    string
  Hobbies []string
}

func main() {
  http.HandleFunc("/", foo)
  http.ListenAndServe(":3000", nil)
}

func foo(w http.ResponseWriter, r *http.Request) {
  profile := Profile{"Alex", []string{"snowboarding", "programming"}}

  fp := path.Join("templates", "index.html")
  tmpl, err := template.ParseFiles(fp)
  if err != nil {
    http.Error(w, err.Error(), http.StatusInternalServerError)
    return
  }

  if err := tmpl.Execute(w, profile); err != nil {
    http.Error(w, err.Error(), http.StatusInternalServerError)
  }
}

测试:

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$ curl -i localhost:3000
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 84

<h1>Hello Alex</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>

使用HTML模板生成字符串

除了上面的把http.ResponseWriter作为模版的执行参数，还可以使用buffer得到渲染的结果。

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...
buf := new(bytes.Buffer)
if err := tmpl.Execute(buf, profile); err != nil {
  http.Error(w, err.Error(), http.StatusInternalServerError)
}
templateString := buf.String()
...

使用嵌套的模版

文件：templates/layout.html

templates/layout.html
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<html>
  <head>
    <title>{ { template "title" . } } </title>
  </head>
  <body
    { { template "content" .  } }
  </body>
</html>

文件：templates/index.html

templates/index.html
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{ { define "title" } }An example layout{ { end } }

{ { define "content" } }
<h1>Hello { { .Name } }</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>
{ { end } }
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package main

import (
  "html/template"
  "net/http"
  "path"
)

type Profile struct {
  Name    string
  Hobbies []string
}

func main() {
  http.HandleFunc("/", foo)
  http.ListenAndServe(":3000", nil)
}

func foo(w http.ResponseWriter, r *http.Request) {
  profile := Profile{"Alex", []string{"snowboarding", "programming"}}

  lp := path.Join("templates", "layout.html")
  fp := path.Join("templates", "index.html")

  // Note that the layout file must be the first parameter in ParseFiles
  tmpl, err := template.ParseFiles(lp, fp)
  if err != nil {
    http.Error(w, err.Error(), http.StatusInternalServerError)
    return
  }

  if err := tmpl.Execute(w, profile); err != nil {
    http.Error(w, err.Error(), http.StatusInternalServerError)
  }
}

测试:

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$ curl -i localhost:3000
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 180

<html>
  <head>
    <title>An example layout</title>
  </head>
  <body>
    <h1>Hello Alex</h1>
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>
  </body>
</html>