ipfs-file-manager/retrive.js

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import { create } from 'ipfs';
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import { writeFile } from 'fs/promises';
import { fileTypeFromBuffer } from 'file-type';
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class IPFSFileManager {
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constructor() {
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this.node = null;
}
async initIPFS() {
this.node = await create();
console.log('IPFS node is ready');
}
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async retrieveFileFromIPFS(cid, filepath) {
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try {
await this.initIPFS();
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const chunks = [];
for await (const chunk of this.node.cat(cid)) {
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chunks.push(chunk);
}
const fileData = Buffer.concat(chunks);
// Determine the file extension based on the MIME type
const { mime } = await this.getfileTypeFromFile(fileData);
const fileExtension = this.getFileExtension(mime);
// Save the file data to a local file with the appropriate extension
const filePath = `${filepath}.${fileExtension}`;
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await this.saveFileToLocal(filePath, fileData);
this.closeIPFS();
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console.log('File retrieved from IPFS and saved as:', filePath);
} catch (error) {
console.error('Failed to retrieve the file from IPFS', error);
}
}
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async saveFileToLocal(filePath, fileData) {
try {
await writeFile(filePath, fileData);
} catch (error) {
console.error('Failed to save the file locally', error);
throw error;
}
}
async getfileTypeFromFile(fileData) {
try {
return fileTypeFromBuffer(fileData);
} catch (error) {
console.error('Failed to determine the file type', error);
throw error;
}
}
getFileExtension(mimeType) {
// Map commonly used MIME types to file extensions
const extensionMap = {
'application/pdf': 'pdf',
'image/jpeg': 'jpg',
'image/png': 'png',
// Add more MIME types and extensions as needed
};
// Return the corresponding extension if available, otherwise fallback to 'dat'
return extensionMap[mimeType] || 'dat';
}
async closeIPFS() {
if (this.node) {
await this.node.stop();
console.log('IPFS node connection closed');
}
}
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}
const cid = 'QmQgGxzWnzjCfouxRiozBiEG3wcsuJGWjtHjv3wurVbJ9s'; // Replace with the CID of the file you want to retrieve
const filepath = './retrievedFile'; // Specify the file path without the extension
const ipfsFileManager = new IPFSFileManager();
ipfsFileManager.retrieveFileFromIPFS(cid, filepath);