GridFS is a specification for storing and retrieving large files in MongoDB. It divides a file into smaller chunks and stores each chunk as a separate document. When working with GridFS in a Node.js environment using Mongoose.js, you can follow these steps: 1. Set Up Your Project First, set up yourRead more
GridFS is a specification for storing and retrieving large files in MongoDB. It divides a file into smaller chunks and stores each chunk as a separate document. When working with GridFS in a Node.js environment using Mongoose.js, you can follow these steps:
1. Set Up Your Project
First, set up your Node.js project if you haven’t already.
mkdir gridfs-examplecd gridfs-example
npm init -y
npm install mongoose gridfs-stream2. Connect to MongoDB
Set up your MongoDB connection using Mongoose.
3. Set Up GridFS Stream
Use gridfs-stream to interact with GridFS.
4. Upload a File to GridFS
Use the gridfs-stream to upload a file.
5. Retrieve a File from GridFS
Use gridfs-stream to read a file.
6. Delete a File from GridFS
Use gfs.remove to delete a file.
Full Example
Here is a complete example incorporating all the steps:
const mongoose = require(‘mongoose’);
const Grid = require(‘gridfs-stream’);
const fs = require(‘fs’);
const path = require(‘path’);
// Connect to MongoDB
mongoose.connect(‘mongodb://localhost:27017/gridfs-example’, {
useNewUrlParser: true,
useUnifiedTopology: true,
});
const conn = mongoose.connection;
Grid.mongo = mongoose.mongo;
let gfs;
conn.once(‘open’, () => {
console.log(‘MongoDB connected’);
gfs = Grid(conn.db);
gfs.collection(‘uploads’);
// Upload a file
const filePath = ‘/path/to/your/file.txt’;
const writeStream = gfs.createWriteStream({
filename: path.basename(filePath),
});
fs.createReadStream(filePath).pipe(writeStream);
writeStream.on(‘close’, (file) => {
console.log(`File ${file.filename} written to DB`);
// Retrieve the file
const filename = file.filename;
const destination = `/path/to/destination/${filename}`;
const readStream = gfs.createReadStream({ filename });
const writeStream = fs.createWriteStream(destination);
readStream.pipe(writeStream);
writeStream.on(‘close’, () => {
console.log(`File ${filename} has been written to ${destination}`);
// Delete the file
gfs.remove({ filename }, (err) => {
if (err) {
console.error(‘Error deleting file:’, err);
} else {
console.log(`File ${filename} deleted from DB`);
}
});
});
});
}
Bitcoin's price volatility stems from a complex interplay of factors that collectively shape its market dynamics. At its core, Bitcoin's value is significantly influenced by market demand and speculative trading activities. Fluctuations can be drastic as investors react to perceived opportunities orRead more
Bitcoin’s price volatility stems from a complex interplay of factors that collectively shape its market dynamics. At its core, Bitcoin’s value is significantly influenced by market demand and speculative trading activities. Fluctuations can be drastic as investors react to perceived opportunities or risks, driving rapid price changes. Moreover, regulatory developments play a pivotal role; positive news such as regulatory acceptance or institutional adoption often boosts prices, while regulatory crackdowns or negative scrutiny can lead to sell-offs.
Market liquidity is another critical determinant, with Bitcoin’s relatively smaller market size compared to traditional assets amplifying price movements in response to large trades. Investor sentiment, influenced by media coverage and social media trends, further fuels volatility, as sentiment shifts can trigger mass buying or selling. Technological factors, such as network upgrades or security vulnerabilities, also impact prices by affecting investor confidence.
Additionally, macro-economic events like global economic instability or inflation concerns can position Bitcoin as a hedge or safe-haven asset, influencing demand. Finally, the decentralized nature of Bitcoin markets can make them susceptible to manipulation, contributing to sudden and dramatic price fluctuations.
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