curl-parser

A Rust library for parsing curl commands into structured HTTP request objects.

Overview

Many APIs provide curl examples to help users get started quickly. This crate bridges the gap between curl command examples and Rust code by parsing curl commands into structured ParsedRequest objects that can be easily converted to HTTP requests.

Features

Parse curl commands into structured Rust objects
Template support for dynamic values (e.g., API tokens)
Automatic conversions for common patterns
reqwest integration (optional)
High performance with optimized parsing

Supported curl Options

-X, --request - HTTP method
-H, --header - HTTP headers
-d, --data - Request body
-u - Basic authentication
-L, --location - Follow redirects
-k, --insecure - Skip SSL verification

Installation

Add this to your Cargo.toml:

[dependencies]
curl-parser = "0.6"

Feature Flags

reqwest (enabled by default) - Enables conversion to reqwest::RequestBuilder
uri (enabled by default) - Parses URLs into http::Uri type

To use without default features:

[dependencies]
curl-parser = { version = "0.6", default-features = false }

Quick Start

Basic Usage

use curl_parser::ParsedRequest;
use std::str::FromStr;

let curl_cmd = "curl https://api.example.com/users";
let request = ParsedRequest::from_str(curl_cmd)?;

println!("Method: {}", request.method);
println!("URL: {}", request.url);

With Template Variables

use curl_parser::ParsedRequest;
use serde_json::json;

let curl_cmd = r#"curl -X POST https://api.github.com/repos \
    -H "Authorization: Bearer {{ token }}" \
    -d '{"name": "{{ repo_name }}"}"#;

let context = json!({
    "token": "your_github_token",
    "repo_name": "my-new-repo"
});

let request = ParsedRequest::load(curl_cmd, context)?;

Convert to reqwest

use curl_parser::ParsedRequest;
use std::str::FromStr;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let curl_cmd = "curl https://api.github.com/users/rust-lang";
    let parsed = ParsedRequest::from_str(curl_cmd)?;

    // Convert to reqwest::RequestBuilder
    let request: reqwest::RequestBuilder = parsed.try_into()?;

    // Send the request
    let response = request.send().await?;
    println!("Status: {}", response.status());

    Ok(())
}

Examples

POST with JSON Body

let curl = r#"curl -X POST https://api.example.com/users \
    -H 'Content-Type: application/json' \
    -H 'Authorization: Bearer token123' \
    -d '{"name": "John Doe", "email": "john@example.com"}"#;

let request = ParsedRequest::from_str(curl)?;
assert_eq!(request.method, Method::POST);
assert_eq!(request.body, vec![r#"{"name": "John Doe", "email": "john@example.com"}"#]);

Basic Authentication

let curl = r#"curl https://api.stripe.com/v1/charges \
    -u sk_test_1234: \
    -H "Stripe-Version: 2022-11-15""#;

let request = ParsedRequest::from_str(curl)?;
// The -u flag is automatically converted to Authorization: Basic header

Form Data

let curl = r#"curl -X POST https://httpbin.org/post \
    -d 'name=John' \
    -d 'age=30' \
    -d 'city=New York'"#;

let request = ParsedRequest::from_str(curl)?;
// Multiple -d flags are collected and form-urlencoded

Advanced Features

Escaped JSON in Headers

The parser correctly handles escaped JSON in headers:

let curl = r#"curl https://api.example.com \
    -H "X-Custom-Data: {\"key\":\"value\",\"nested\":{\"data\":true}}"#;

let request = ParsedRequest::from_str(curl)?;
// The escaped JSON is properly unescaped in the header value

Automatic Method Inference

If a request body is provided without an explicit method, POST is automatically used:

let curl = r#"curl https://api.example.com -d '{"data": "value"}'"#;
let request = ParsedRequest::from_str(curl)?;
assert_eq!(request.method, Method::POST); // Automatically set to POST

Default Headers

The parser automatically adds common default headers:

Accept: */* if not specified
Content-Type: application/x-www-form-urlencoded for form data

Performance

This crate is optimized for performance with:

Cached template environment (60%+ improvement for template operations)
Pre-allocated collections for common sizes
Efficient string operations using byte-level matching
Optimized grammar rules for the Pest parser

Run benchmarks with:

cargo bench --bench parsing_benchmark

Development

Building

cargo build

Testing

cargo test

Linting

cargo clippy
cargo fmt

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

Built with Pest parser
Template support via minijinja
Inspired by the need to quickly convert API documentation to working code

curl-parser 0.6.0