How does cohttp handle HTTP redirects?

Cohttp does not automatically follow redirects. You need to implement custom logic, as shown in the README tutorials with examples for Lwt and Async backends, which can add boilerplate code.

cohttp vs httpaf: which is better for OCaml HTTP?

Cohttp is higher-level and portable across multiple async backends, ideal for cross-platform projects. Httpaf is lower-level and optimized for performance with Lwt, better for Lwt-specific applications where speed is critical.

How to create a custom resolver for cohttp?

Implement a custom IO backend using the IO signature from lib/s.mli. The README includes a Docker socket client example that customizes the resolver to map hostnames to Unix domain sockets.

Does cohttp support HTTPS out of the box?

Yes, it integrates with ocaml-tls and async_ssl for HTTPS, depending on the backend. For Lwt, it defaults to ocaml-ssl but can use ocaml-tls, and for Async, it uses async_ssl.

How to compile cohttp for JavaScript with Js_of_ocaml?

Use the Cohttp_lwt_jsoo module, which maps Cohttp calls to XMLHttpRequests. Install the cohttp-lwt-jsoo package and follow Js_of_ocaml compilation steps to target web browsers or Node.js.

What's the difference between cohttp-lwt and cohttp-async?

Cohttp-lwt uses the Lwt library and is OS-independent, suitable for MirageOS and UNIX. Cohttp-async uses the Async library, primarily for UNIX systems, with different concurrency semantics and TLS implementations.

How to debug cohttp servers effectively?

Set the COHTTP_DEBUG environment variable to enable default logging, or customize using the Logs library as described in the README, including examples for filtering cohttp-specific logs.

ocaml-cohttp — OCaml HTTP Client & Server Library

What is ocaml-cohttp?

ocaml-cohttp is a comprehensive OCaml library for creating HTTP clients and servers. It provides a portable, dependency-free HTTP parser and supports multiple asynchronous backends like Lwt, Async, Eio, and Js_of_ocaml, enabling deployment across diverse targets from UNIX systems to MirageOS unikernels and JavaScript compilation.

Target Audience

OCaml developers building HTTP-based applications, including those targeting web services, MirageOS unikernels, or JavaScript environments via Js_of_ocaml. It's suitable for projects requiring flexible concurrency models and cross-platform compatibility.

Value Proposition

Developers choose ocaml-cohttp for its portability, minimal dependencies, and support for multiple asynchronous libraries, allowing them to select the best backend for their specific use case while maintaining a consistent HTTP interface. Its extensible architecture and included utility binaries for testing further streamline development.

An OCaml library for HTTP clients and servers using Lwt or Async

Use Cases

Best For

Building HTTP servers and clients in OCaml with support for multiple asynchronous backends like Lwt, Async, and Eio.
Developing applications for MirageOS unikernels that require HTTP communication capabilities.
Compiling OCaml HTTP libraries to JavaScript via Js_of_ocaml for web-based projects.
Creating cross-platform HTTP tools that run on UNIX systems, unikernels, and in JavaScript environments.
Implementing custom HTTP backends or resolvers, such as for Docker socket communication or other specialized protocols.
Testing and debugging HTTP interactions with included curl-like client and simple server binaries.

Not Ideal For

Projects requiring built-in support for multipart form data or session management without external dependencies
Teams seeking a batteries-included web framework with pre-built routing and middleware
Simple HTTP use cases where a single, lightweight async backend would suffice without configuration overhead

Pros & Cons

Pros

Portable HTTP Parser

The parser is fast and dependency-free, enabling easy interoperability with other OCaml packages and simplifying integration.

Flexible Async Backends

Supports Lwt, Async, Eio, and Js_of_ocaml, allowing developers to choose the concurrency model best suited for their platform, from UNIX to JavaScript.

Cross-Platform Deployment

Works on UNIX systems, MirageOS unikernels, and compiles to JavaScript via Js_of_ocaml, making it versatile for diverse target environments.

Extensible Architecture

The IO signature enables easy implementation of custom backends, as demonstrated in the Docker socket client example for specialized resolvers.

Cons

Missing Common Features

Multipart form data and session management are not built-in, requiring integration with external libraries like multipart_form or ocaml-session, increasing setup complexity.

Manual Redirect Handling

HTTP redirects are not automatically managed; developers must implement custom logic, as admitted in the README with tutorial examples for both Lwt and Async backends.

Backend Configuration Overhead

With multiple async backends available, selecting and configuring the right one can be daunting, especially for newcomers to OCaml's concurrency ecosystem.

Frequently Asked Questions

What is ocaml-cohttp?

Target Audience

Value Proposition

Use Cases

Best For

Building HTTP servers and clients in OCaml with support for multiple asynchronous backends like Lwt, Async, and Eio.
Developing applications for MirageOS unikernels that require HTTP communication capabilities.
Compiling OCaml HTTP libraries to JavaScript via Js_of_ocaml for web-based projects.
Creating cross-platform HTTP tools that run on UNIX systems, unikernels, and in JavaScript environments.
Implementing custom HTTP backends or resolvers, such as for Docker socket communication or other specialized protocols.
Testing and debugging HTTP interactions with included curl-like client and simple server binaries.

Not Ideal For

Projects requiring built-in support for multipart form data or session management without external dependencies
Teams seeking a batteries-included web framework with pre-built routing and middleware
Simple HTTP use cases where a single, lightweight async backend would suffice without configuration overhead

Pros & Cons

Pros

Portable HTTP Parser

The parser is fast and dependency-free, enabling easy interoperability with other OCaml packages and simplifying integration.

Flexible Async Backends

Supports Lwt, Async, Eio, and Js_of_ocaml, allowing developers to choose the concurrency model best suited for their platform, from UNIX to JavaScript.

Cross-Platform Deployment

Works on UNIX systems, MirageOS unikernels, and compiles to JavaScript via Js_of_ocaml, making it versatile for diverse target environments.

Extensible Architecture

The IO signature enables easy implementation of custom backends, as demonstrated in the Docker socket client example for specialized resolvers.

Cons

Missing Common Features

Multipart form data and session management are not built-in, requiring integration with external libraries like multipart_form or ocaml-session, increasing setup complexity.

Manual Redirect Handling

HTTP redirects are not automatically managed; developers must implement custom logic, as admitted in the README with tutorial examples for both Lwt and Async backends.

Backend Configuration Overhead

With multiple async backends available, selecting and configuring the right one can be daunting, especially for newcomers to OCaml's concurrency ecosystem.

Frequently Asked Questions

ocaml-cohttp

What is ocaml-cohttp?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Found a gem we're missing?

ocaml-cohttp

What is ocaml-cohttp?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Found a gem we're missing?