Node模塊（一）——request

最近與Node項目接觸的比較多，故決定介紹一些用到的node模塊，並附帶一些使用時的經驗。
首先用到的一個就是request，當在node中調用其他系統接口或進行一些交互時，所能採用的一種http/https請求方式。

簡單示例

var request = require('request');
request('http://www.google.com', function (error, response, body) {
  console.log('error:', error); // Print the error if one occurred
  console.log('statusCode:', response && response.statusCode); // Print the response status code if a response was received
  console.log('body:', body); // Print the HTML for the Google homepage.
});

流

可以把響應轉化成文件流：

request('http://google.com/doodle.png').pipe(fs.createWriteStream('doodle.png'))

也可以將文件流寫入post或put方法，但要使用合適的content-type。

fs.createReadStream('file.json').pipe(request.put('http://mysite.com/obj.json'))

請求也可以傳輸自己，此時put的header裏要有content-type和content-length。

request.get('http://google.com/img.png').pipe(request.put('http://mysite.com/img.png'))

請求會產生響應事件：

request
  .get('http://google.com/img.png')
  .on('response', function(response) {
    console.log(response.statusCode) // 200
    console.log(response.headers['content-type']) // 'image/png'
  })
  .pipe(request.put('http://mysite.com/img.png'))

若要處理錯誤，則

request
  .get('http://mysite.com/doodle.png')
  .on('error', function(err) {
    console.log(err)
  })
  .pipe(fs.createWriteStream('doodle.png'))

綜合示例：

http.createServer(function (req, resp) {
  if (req.url === '/doodle.png') {
    if (req.method === 'PUT') {
      req.pipe(request.put('http://mysite.com/doodle.png'))
    } else if (req.method === 'GET' || req.method === 'HEAD') {
      request.get('http://mysite.com/doodle.png').pipe(resp)
    }
  }
})

pipe可用於http 請求和響應對象。

http.createServer(function (req, resp) {
  if (req.url === '/doodle.png') {
    var x = request('http://mysite.com/doodle.png')
    req.pipe(x)
    x.pipe(resp)
  }
})

代理：

req.pipe(request('http://mysite.com/doodle.png')).pipe(resp)

表單

application/x-www-form-urlencoded (URL-Encoded Forms)

request.post('http://service.com/upload', {form:{key:'value'}})
// or
request.post('http://service.com/upload').form({key:'value'})
// or
request.post({url:'http://service.com/upload', form: {key:'value'}}, function(err,httpResponse,body){ /* ... */ })

multipart/form-data (Multipart Form Uploads)

大部分情況下可以把表單數據放到formData裏。

var formData = {
  // Pass a simple key-value pair
  my_field: 'my_value',
  // Pass data via Buffers
  my_buffer: Buffer.from([1, 2, 3]),
  // Pass data via Streams
  my_file: fs.createReadStream(__dirname + '/unicycle.jpg'),
  // Pass multiple values /w an Array
  attachments: [
    fs.createReadStream(__dirname + '/attachment1.jpg'),
    fs.createReadStream(__dirname + '/attachment2.jpg')
  ],
  // Pass optional meta-data with an 'options' object with style: {value: DATA, options: OPTIONS}
  // Use case: for some types of streams, you'll need to provide "file"-related information manually.
  // See the `form-data` README for more information about options: https://github.com/form-data/form-data
  custom_file: {
    value:  fs.createReadStream('/dev/urandom'),
    options: {
      filename: 'topsecret.jpg',
      contentType: 'image/jpeg'
    }
  }
};
request.post({url:'http://service.com/upload', formData: formData}, function optionalCallback(err, httpResponse, body) {
  if (err) {
    return console.error('upload failed:', err);
  }
  console.log('Upload successful!  Server responded with:', body);
});

可以通過form()獲取表單數據，在下一次請求時就會更改。

// NOTE: Advanced use-case, for normal use see 'formData' usage above
var r = request.post('http://service.com/upload', function optionalCallback(err, httpResponse, body) {...})
var form = r.form();
form.append('my_field', 'my_value');
form.append('my_buffer', Buffer.from([1, 2, 3]));
form.append('custom_file', fs.createReadStream(__dirname + '/unicycle.jpg'), {filename: 'unicycle.jpg'});

multipart/related

變量有回車換行所需

 request({
    method: 'PUT',
    preambleCRLF: true,
    postambleCRLF: true,
    uri: 'http://service.com/upload',
    multipart: [
      {
        'content-type': 'application/json',
        body: JSON.stringify({foo: 'bar', _attachments: {'message.txt': {follows: true, length: 18, 'content_type': 'text/plain' }}})
      },
      { body: 'I am an attachment' },
      { body: fs.createReadStream('image.png') }
    ],
    // alternatively pass an object containing additional options
    multipart: {
      chunked: false,
      data: [
        {
          'content-type': 'application/json',
          body: JSON.stringify({foo: 'bar', _attachments: {'message.txt': {follows: true, length: 18, 'content_type': 'text/plain' }}})
        },
        { body: 'I am an attachment' }
      ]
    }
  },
  function (error, response, body) {
    if (error) {
      return console.error('upload failed:', error);
    }
    console.log('Upload successful!  Server responded with:', body);
  })

http認證

request.get('http://some.server.com/').auth('username', 'password', false);
// or
request.get('http://some.server.com/', {
  'auth': {
    'user': 'username',
    'pass': 'password',
    'sendImmediately': false
  }
});
// or
request.get('http://some.server.com/').auth(null, null, true, 'bearerToken');
// or
request.get('http://some.server.com/', {
  'auth': {
    'bearer': 'bearerToken'
  }
});

也可以把用戶名和密碼拼到URL當中

var username = 'username',
    password = 'password',
    url = 'http://' + username + ':' + password + '@some.server.com';
 
request({url: url}, function (error, response, body) {
   // Do more stuff with 'body' here
});

規定http頭

var request = require('request');
 
var options = {
  url: 'https://api.github.com/repos/request/request',
  headers: {
    'User-Agent': 'request'
  }
};
 
function callback(error, response, body) {
  if (!error && response.statusCode == 200) {
    var info = JSON.parse(body);
    console.log(info.stargazers_count + " Stars");
    console.log(info.forks_count + " Forks");
  }
}
 
request(options, callback);

授權標記

// OAuth1.0 - 3-legged server side flow (Twitter example)
// step 1
var qs = require('querystring')
  , oauth =
    { callback: 'http://mysite.com/callback/'
    , consumer_key: CONSUMER_KEY
    , consumer_secret: CONSUMER_SECRET
    }
  , url = 'https://api.twitter.com/oauth/request_token'
  ;
request.post({url:url, oauth:oauth}, function (e, r, body) {
  // Ideally, you would take the body in the response
  // and construct a URL that a user clicks on (like a sign in button).
  // The verifier is only available in the response after a user has
  // verified with twitter that they are authorizing your app.
 
  // step 2
  var req_data = qs.parse(body)
  var uri = 'https://api.twitter.com/oauth/authenticate'
    + '?' + qs.stringify({oauth_token: req_data.oauth_token})
  // redirect the user to the authorize uri
 
  // step 3
  // after the user is redirected back to your server
  var auth_data = qs.parse(body)
    , oauth =
      { consumer_key: CONSUMER_KEY
      , consumer_secret: CONSUMER_SECRET
      , token: auth_data.oauth_token
      , token_secret: req_data.oauth_token_secret
      , verifier: auth_data.oauth_verifier
      }
    , url = 'https://api.twitter.com/oauth/access_token'
    ;
  request.post({url:url, oauth:oauth}, function (e, r, body) {
    // ready to make signed requests on behalf of the user
    var perm_data = qs.parse(body)
      , oauth =
        { consumer_key: CONSUMER_KEY
        , consumer_secret: CONSUMER_SECRET
        , token: perm_data.oauth_token
        , token_secret: perm_data.oauth_token_secret
        }
      , url = 'https://api.twitter.com/1.1/users/show.json'
      , qs =
        { screen_name: perm_data.screen_name
        , user_id: perm_data.user_id
        }
      ;
    request.get({url:url, oauth:oauth, qs:qs, json:true}, function (e, r, user) {
      console.log(user)
    })
  })
})

根據不同的認證算法，可在配置中加相應參數。

TSL/SSL協議

使用一個options來設置協議的各種參數。

var fs = require('fs')
    , path = require('path')
    , certFile = path.resolve(__dirname, 'ssl/client.crt')
    , keyFile = path.resolve(__dirname, 'ssl/client.key')
    , caFile = path.resolve(__dirname, 'ssl/ca.cert.pem')
    , request = require('request');
 
var options = {
    url: 'https://api.some-server.com/',
    cert: fs.readFileSync(certFile),
    key: fs.readFileSync(keyFile),
    passphrase: 'password',
    ca: fs.readFileSync(caFile)
};
 
request.get(options);

使用options.agentOptions

var fs = require('fs')
    , path = require('path')
    , certFile = path.resolve(__dirname, 'ssl/client.crt')
    , keyFile = path.resolve(__dirname, 'ssl/client.key')
    , request = require('request');
 
var options = {
    url: 'https://api.some-server.com/',
    agentOptions: {
        cert: fs.readFileSync(certFile),
        key: fs.readFileSync(keyFile),
        // Or use `pfx` property replacing `cert` and `key` when using private key, certificate and CA certs in PFX or PKCS12 format:
        // pfx: fs.readFileSync(pfxFilePath),
        passphrase: 'password',
        securityOptions: 'SSL_OP_NO_SSLv3'
    }
};
 
request.get(options);

最後例子

var request = require('request')
  request(
    { method: 'GET'
    , uri: 'http://www.google.com'
    , gzip: true
    }
  , function (error, response, body) {
      // body is the decompressed response body
      console.log('server encoded the data as: ' + (response.headers['content-encoding'] || 'identity'))
      console.log('the decoded data is: ' + body)
    }
  )
  .on('data', function(data) {
    // decompressed data as it is received
    console.log('decoded chunk: ' + data)
  })
  .on('response', function(response) {
    // unmodified http.IncomingMessage object
    response.on('data', function(data) {
      // compressed data as it is received
      console.log('received ' + data.length + ' bytes of compressed data')
    })
  })

 var request = require('request')
    , rand = Math.floor(Math.random()*100000000).toString()
    ;
  request(
    { method: 'PUT'
    , uri: 'http://mikeal.iriscouch.com/testjs/' + rand
    , multipart:
      [ { 'content-type': 'application/json'
        ,  body: JSON.stringify({foo: 'bar', _attachments: {'message.txt': {follows: true, length: 18, 'content_type': 'text/plain' }}})
        }
      , { body: 'I am an attachment' }
      ]
    }
  , function (error, response, body) {
      if(response.statusCode == 201){
        console.log('document saved as: http://mikeal.iriscouch.com/testjs/'+ rand)
      } else {
        console.log('error: '+ response.statusCode)
        console.log(body)
      }
    }
  )