Convert nodejs network pictures into picture streams

In modern web applications, there are also some old websites and applications that still use traditional methods to convert images on the network into local image storage and processing. However, in the Node.js environment, we can easily store network images directly on the server by converting them into image streams.

In this article, we will discuss how to use Node.js to convert network images into image streams and store them in files or databases.

First, we need to install some Node.js modules to handle the conversion process of network images and image streams. The following is a list of modules that need to be installed:

1. request – used to obtain image data from the network
2. sharp – image processing library, used to convert images to streams and other formats

Use the npm command to install these two libraries:

npm install request sharp

After such a simple installation, we can start using these two Node.js modules to convert network images into Picture stream. The following is a sample code:

const request = require('request');
const sharp = require('sharp');

const url = 'https://yourwebsite.com/image.jpg';
const options = {
  url: url,
  encoding: null
};

request.get(options, (err, response, buffer) => {
  if (err) throw err;
  
  sharp(buffer)
    .png()
    .toBuffer((err, data, info) => {
      if (err) throw err;
      
      // 在此处，我们可以将data写入文件或数据库
      // 例如，如果要将图片存储到文件夹中：
      // fs.writeFileSync('test.png', data);
      
      // 或者，如果要将图片存储到MongoDB数据库中：
      // const collection = db.collection('images');
      // collection.insertOne({ data: data });
    });
});

In this sample code, we first use the request library to load image data from the specified URL. We specified encoding as null because we need to obtain the original binary image data instead of converting it to text or JSON format. After obtaining the image data, we use the sharp module to convert it into a PNG format stream so that we can store or process it in subsequent operations.

In the above example code, we can write the stream to a file or MongoDB database. To write stream data to a file, you can use the fs.writeFileSync() function of the fs module to create a new file and write the stream data. To write streaming data into the MongoDB database, we first need to create a MongoDB connection, then select a collection (such as mycollection), and then call the insertOne() function of the database to add Data is written to the database. The data here is the Buffer instance object data generated by the streams above.

Now you know how to convert network images into image streams and store or process them in the Node.js environment. This is very useful for web applications that need to process network images. Keep in mind that you can perform other operations on the image stream, such as compression, scaling, or rotation, before converting it to another format.

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