node.js 将图像写入本地服务器

Writing image to local server

提问by Mark

Update

更新

The accepted answer was good for last year but today I would use the package everyone else uses: https://github.com/mikeal/request

去年接受的答案很好，但今天我会使用其他人使用的包：https: //github.com/mikeal/request

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Original

原来的

I'm trying to grab google's logo and save it to my server with node.js.

我正在尝试获取 google 的徽标并使用 node.js 将其保存到我的服务器。

This is what I have right now and doesn't work:

这是我现在所拥有的，但不起作用：

        var options = {
            host: 'google.com',
            port: 80,
            path: '/images/logos/ps_logo2.png'
        };

        var request = http.get(options);

        request.on('response', function (res) {
            res.on('data', function (chunk) {
                fs.writeFile(dir+'image.png', chunk, function (err) {
                    if (err) throw err;
                    console.log('It\'s saved!');
                });
            });
        });

How can I get this working?

我怎样才能让它工作？

回答by Ricardo Tomasi

A few things happening here:

这里发生了一些事情：

1. I assume you required fs/http, and set the dir variable :)
2. google.com redirects to www.google.com, so you're saving the redirect response's body, not the image
3. the response is streamed. that means the 'data' event fires many times, not once. you have to save and join all the chunks together to get the full response body
4. since you're getting binary data, you have to set the encoding accordingly on response and writeFile (default is utf8)

1. 我假设您需要 fs/http，并设置 dir 变量:)
2. google.com 重定向到 www.google.com，因此您保存的是重定向响应的正文，而不是图像
3. 响应是流式传输的。这意味着“数据”事件会触发多次，而不是一次。您必须保存并将所有块连接在一起才能获得完整的响应正文
4. 由于您正在获取二进制数据，因此您必须在 response 和 writeFile 上相应地设置编码（默认为 utf8）

This should work:

这应该有效：

var http = require('http')
  , fs = require('fs')
  , options

options = {
    host: 'www.google.com'
  , port: 80
  , path: '/images/logos/ps_logo2.png'
}

var request = http.get(options, function(res){
    var imagedata = ''
    res.setEncoding('binary')

    res.on('data', function(chunk){
        imagedata += chunk
    })

    res.on('end', function(){
        fs.writeFile('logo.png', imagedata, 'binary', function(err){
            if (err) throw err
            console.log('File saved.')
        })
    })

})

回答by m4tm4t

This thread is old but I wanted to do same things with the https://github.com/mikeal/requestpackage.

这个线程很旧，但我想用https://github.com/mikeal/request包做同样的事情。

Here a working example

这是一个工作示例

var fs      = require('fs');
var request = require('request');
// Or with cookies
// var request = require('request').defaults({jar: true});

request.get({url: 'https://someurl/somefile.torrent', encoding: 'binary'}, function (err, response, body) {
  fs.writeFile("/tmp/test.torrent", body, 'binary', function(err) {
    if(err)
      console.log(err);
    else
      console.log("The file was saved!");
  }); 
});

回答by Drasill

I suggest you use http-request, so that even redirects are managed.

我建议您使用http-request，以便甚至可以管理重定向。

var http = require('http-request');
var options = {url: 'http://localhost/foo.pdf'};
http.get(options, '/path/to/foo.pdf', function (error, result) {
    if (error) {
        console.error(error);
    } else {
        console.log('File downloaded at: ' + result.file);
    }
});

回答by yuqin

How about this?

这个怎么样？

var http = require('http'), 
fs = require('fs'), 
options;

options = {
    host: 'www.google.com' , 
    port: 80,
    path: '/images/logos/ps_logo2.png'
}

var request = http.get(options, function(res){

//var imagedata = ''
//res.setEncoding('binary')

var chunks = [];

res.on('data', function(chunk){

    //imagedata += chunk
    chunks.push(chunk)

})

res.on('end', function(){

    //fs.writeFile('logo.png', imagedata, 'binary', function(err){

    var buffer = Buffer.concat(chunks)
    fs.writeFile('logo.png', buffer, function(err){
        if (err) throw err
        console.log('File saved.')
    })

})

回答by BlackBeard

Cleanestway of saving image locally using request:

使用request在本地保存图像的最干净方式：

const request = require('request');
request('http://link/to/your/image/file.png').pipe(fs.createWriteStream('fileName.png'))

If you need to add authentication tokenin headers do this:

如果您需要在标头中添加身份验证令牌，请执行以下操作：

const request = require('request');
request({
        url: 'http://link/to/your/image/file.png',
        headers: {
            "X-Token-Auth": TOKEN,
        }
    }).pipe(fs.createWriteStream('filename.png'))                    

回答by Under-qualified NASA Intern

I have an easier solution using fs.readFileSync(./my_local_image_path.jpg)

我有一个更简单的解决方案 fs.readFileSync(./my_local_image_path.jpg)

This is for reading images from Azure Cognative Services's Vision API

这是用于从Azure 认知服务的 Vision API读取图像

const subscriptionKey = 'your_azure_subscrition_key';
const uriBase = // **MUST change your location (mine is 'eastus')**
    'https://eastus.api.cognitive.microsoft.com/vision/v2.0/analyze';

// Request parameters.
const params = {
    'visualFeatures': 'Categories,Description,Adult,Faces',
    'maxCandidates': '2',
    'details': 'Celebrities,Landmarks',
    'language': 'en'
};

const options = {
    uri: uriBase,
    qs: params,
    body: fs.readFileSync(./my_local_image_path.jpg),
    headers: {
        'Content-Type': 'application/octet-stream',
        'Ocp-Apim-Subscription-Key' : subscriptionKey
    }
};

request.post(options, (error, response, body) => {
if (error) {
    console.log('Error: ', error);
    return;
}
let jsonString = JSON.stringify(JSON.parse(body), null, '  ');
body = JSON.parse(body);
if (body.code) // err
{
    console.log("AZURE: " + body.message)
}

console.log('Response\n' + jsonString);