Skip to content
Experimental web framework for ReasonML & OCaml
OCaml Standard ML Reason JavaScript
Branch: master
Clone or download
Type Name Latest commit message Commit time
Failed to load latest commit information.
ReWeb Update ReWeb Manual library name also Feb 8, 2020
ReWebTest Output test results as JUnit Feb 4, 2020
bin Disambiguate library names Feb 8, 2020
esy.lock Output test results as JUnit Feb 4, 2020
examples Lowercase opam package name Jan 4, 2020
.gitignore Output test results as JUnit Feb 4, 2020
MIT-LICENSE Update docs Jan 4, 2020 Fix badge href Feb 4, 2020
azure-pipelines.yml Implement cache-control and server response headers Jan 9, 2020
dune-project update to dune 2.1 (#13) Jan 29, 2020
package.json Move junit dep to devDep Feb 5, 2020
re-web.opam Lowercase opam package name Jan 4, 2020

ReWeb - a type-safe ergonomic ReasonML and OCaml web framework (WIP)

Build Status Test Status

ReWeb is a web framework based on several foundations:

  • The amazing work of the people behind Httpaf, H2, Esy, and others
  • The core idea of 'Your server as a function' by Marius Eriksen which was also the idea behind Twitter's Finagle web stack
  • Jasim Basheer's essay 'Rails on OCaml' which identifies the need for an ergonomic, Rails-like web framework that still preserves the type safety benefits of OCaml.

ReWeb's main concepts are:

  • Services: a service is a function from a request to a promise of response (i.e. an asynchronous function).
  • Filters: a filter is a function that takes a service as input and returns a service as output. It can be inserted into the 'request pipeline' and manipulate the request before the service finally handles it.
  • Server: a server is a function that takes a route (pair of HTTP method and path list) as input and returns a service as output.
  • Type-safe request pipeline: requests have a type parameter that reveals their 'context' i.e. some data that's stored inside them. Filters and services must change requests correctly and in the right order, or the compiler will present type errors.

Notice that all the main concepts here are just functions. They are all composeable using just function composition. Services can call other services. Filters can slot together by calling each other. Servers can delegate smaller scopes to other servers. See bin/ for examples of all of these.



Fullstack Reason

Check out the demo repo which shows a fullstack Reason setup with ReWeb and ReasonReact, with code sharing:

This repo can be cloned and used right away for a new project.

Examples directory

Check out the examples/ directory for small, self-contained basic examples.

Bin directory

Finally, check out the example server in the bin/ directory. The file there has extensive examples of almost everything ReWeb currently supports.

Run the example server:

$ esy bin

Send some requests to it:

$ curl localhost:8080/hello
$ curl localhost:8080/auth/hello
$ curl --user 'bob:secret' localhost:8080/auth/hello

Go to http://localhost:8080/login in your browser, etc.


You need Esy, you can install the beta using npm:

$ npm install --global esy@latest

Then run the esy command from this project root to install and build dependencies.

$ esy

Now you can run your editor within the environment (which also includes merlin):

$ esy $EDITOR
$ esy vim

Alternatively you can try vim-reasonml which loads esy project environments automatically.

After you make some changes to source code, you can re-run project's build again with the same simple esy command.

$ esy

Generate documentation:

$ esy doc
$ esy open '#{self.target_dir}/default/_doc/_html/index.html'

Shell into environment:

$ esy shell

Run the test suite with:

$ esy test


ReWeb is experimental and not for production use! I am still ironing out the API. But (imho) it looks promising for real-world usage.

You can’t perform that action at this time.