Convert nodejs buffer to hexadecimal

In Node.js, Buffer is a class used to process binary data. When dealing with binary data, we often need to convert the data to hexadecimal format. This article will introduce how to use the built-in method of Node.js to convert a Buffer into a hexadecimal string.

1. Using the toString method

The Buffer class provides the toString method, which can convert the Buffer object into a string in the specified encoding format. If the specified encoding format is hex, the toString method will return a string in hexadecimal format.

The following is a sample code:

const buffer = Buffer.from('hello', 'utf8');
const hexString = buffer.toString('hex');
console.log(hexString); // 68656c6c6f

First, we create a Buffer object containing the string "hello". Then, we call the toString method and pass in "hex" as the parameter. Finally, we print the converted hex string.

2. Use the readUInt8 method

readUInt8 is an instance method in the Buffer class that can read the 8-bit unsigned integer at the specified index and convert it to ten A string in hexadecimal format.

The following is a sample code:

const buffer = Buffer.from('hello', 'utf8');
let hexString = '';
for (let i = 0; i < buffer.length; i++) {
  const hex = buffer.readUInt8(i).toString(16);
  hexString += (hex.length === 1 ? '0' + hex : hex);
}
console.log(hexString); // 68656c6c6f

First, we create a Buffer object containing the string "hello". We then use a for loop to iterate through each byte in the Buffer object. In the loop body, we use the readUInt8 method to read the 8-bit unsigned integer at the current index and convert it to a string in hexadecimal format. Finally, we concatenate each byte of the hex string into a complete string and print it out.

3. Use the toString method and the Buffer.slice method

In addition to using the toString method, we can also use the Buffer.slice method to obtain a new Buffer object and convert it A string in hexadecimal format.

The following is a sample code:

const buffer = Buffer.from('hello', 'utf8');
const hexString = buffer.slice(0, buffer.length).toString('hex');
console.log(hexString); // 68656c6c6f

First, we create a Buffer object containing the string "hello". We then use the slice method to get a new Buffer object that contains all the bytes in the original Buffer object. Finally, we convert the new Buffer object into a string in hexadecimal format and print it out.

Summary

This article introduces three methods of converting Node.js Buffer objects to hexadecimal format strings. Using the toString method is the simplest method and the most commonly used method. Using the readUInt8 method and the Buffer.slice method requires more code, but can handle binary data more flexibly. In actual development, we can choose appropriate methods to process binary data according to different needs.

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