golang-http-server

⚠️ This is NOT A PRODUCTION PROJECT. It's a personal project I'm building to practice and become proficient in Go

A minimal HTTP server implemented using Go’s net/http package. Implemented to understand how handlers, middleware, concurrency, and context propagation work in Go.

Features

Endpoints:

• /health: Returns OK if server is running.

• /stats: endpoint that returns the request metrics like total requests, successful requests and Unauthorized requests in JSON.

• /work: endpoint that simulates a CPU bound work with context cancellation. Server stops computation immediately when the client disconnects. It also has an optional query "limit=" to set the number of computations that must be performed.
  For example http://localhost:4000/work?limit=1000 will compute the first 1000 prime numbers.

• /upload: Recieves the file in the POST request form field. Creates a temporary file with a unique name in the ./uploads directory using os.CreateTemp and copies the file to it using io.Copy(). Renames the temp file using os.Rename() with a safe name created by a helper method in the format ./uploads/uuid_originalFileName.extension. uuid is a unique ID generated by google/uuid to maintain unique file names. Performs clean up when the function returns.

• /download: Recieves the file name from the incoming request's file query. Checks if the file exists, using os.Stat(). If the file exists, it uses http.ServeFile() to send the file to the client.

Middlewares:

• AuthMiddleware(): protects the endpoints and returns 401 if the Basic Auth credentials are invalid. The password has been hardcoded because this is just a practice/learning project and I wanted to focus on other important concepts such as file uploading and downloading.

• LoggingMiddleware(): logs the request's method, path, timestamp and time taken to complete the request.

• StatsMiddleware(): the outermost middleware that checks the request's status code and updates the in-memory counters using atomic.AddInt64() to keep track of the metrics.

• MaxBodySize(): Limits the incoming request's body size to 50 << 20 bytes in order to prevent DoS

Packages used

• net/http
• context
• sync/atomic
• path/filepath
• encoding/json
• github.com/google/uuid
• strconv
• regexp
• strings
• os
• io
• time
• log

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Usage example

• Clone Repository

git clone https://github.com/aDiThYa-808/golang-http-server.git

• Start server

go run ./cmd/server

• Upload file

curl -X POST http://localhost:4000/upload -F "file=@example.pdf"

• Download file

curl -o output.pdf http://localhost:4000/download?file=example.pdf

• View metrics

curl -u admin:pass http://localhost:4000/stats

Note: the password is hardcoded only because this project was made for learning purpose.

• Simulate work(compute prime numbers)

curl http://localhost:4000/work?limit=50000

• Health check

curl -u admin:pass http://localhost:4000/health

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Thank you