https://github.com/jneira/wai-servlet
Library to integrate eta wai applications with servlet api
https://github.com/jneira/wai-servlet
eta-lang haskell interop java servlet wai
Last synced: 3 months ago
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Library to integrate eta wai applications with servlet api
- Host: GitHub
- URL: https://github.com/jneira/wai-servlet
- Owner: jneira
- License: bsd-3-clause
- Created: 2017-02-02T05:30:43.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2019-01-09T09:48:34.000Z (almost 7 years ago)
- Last Synced: 2025-07-05T09:05:08.490Z (3 months ago)
- Topics: eta-lang, haskell, interop, java, servlet, wai
- Language: Haskell
- Homepage:
- Size: 149 KB
- Stars: 18
- Watchers: 3
- Forks: 1
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# wai-servlet
[](https://circleci.com/gh/eta-lang/wai-servlet)
Library to integrate [eta](http://eta-lang.org) [wai](https://github.com/yesodweb/wai) applications with the [servlet api](http://docs.oracle.com/javaee/7/api/javax/servlet/package-summary.html)
## Getting Started
* Visit the [Getting Started](https://eta-lang.org/docs/eta-concepts/getting-started/install-eta) eta instructions to build and install the library and the examples
* In [src/Network/Wai/Servlet/Examples.hs](https://github.com/jneira/wai-servlet/blob/master/src/Network/Wai/Servlet/Examples.hs) you can find some examples of wai applications and code to generate a servlet class that can be deployed in your favorite servlet container.
* There are two options to deploy wai-servlet apps: generating a war file to be deployed in a servlet container or run it directly in a embedded one; this is the way more similar to use [wai warp](https://github.com/yesodweb/wai/tree/master/warp) for haskell wai applications.
### Running an application in a embedded servlet container
* You need to install and set the [wai-servlet-jetty-adapter](https://github.com/jneira/wai-servlet-handler-jetty) package as a dependency. Currently is the unique adapter implemented for wai-servlet.
* You have to import the module `Network.Wai.Servlet.Handler.Jetty` with the `run` function and call it with the port server and your application:
```haskell
{-# LANGUAGE OverloadedStrings #-}
import Network.HTTP.Types (status200)
import Network.Wai
import Network.Wai.Servlet
import Network.Wai.Servlet.Handler.Jetty
appSimple :: Application
appSimple _ respond = respond $
responseLBS status200 [("Content-Type", "text/plain")] "Hello World"
main = run 3000 appSimple
```
### Generating a war to be deployed in a servlet container
* This option supposes some manual steps. There is plans to make etlas build automatically a war file, tracked in [this issue](https://github.com/typelead/eta/issues/265).
* The main function to generate the servlet is `Network.Wai.Servlet.makeServiceMethod` for example:
```haskell
{-# LANGUAGE OverloadedStrings #-}
import Java
import Network.Wai
import Network.HTTP.Types (status200)
import Network.Wai.Servlet
appSimple :: Application
appSimple _ respond = respond $
responseLBS status200 [("Content-Type", "text/plain")] "Hello World"
servSimple :: DefaultWaiServletApplication
servSimple = makeServiceMethod appSimple
foreign export java "service" servSimple :: DefaultWaiServletApplication
```
* This code will generate a `network.wai.servlet.DefaultWaiServlet` java class that extends `javax.servlet.GenericServlet` suitable to use in a standard war file
* To generate the war you have to create the standard directory structure:
* webApp
* static resources (jsp,html,etc)
* META-INF
* WEB-INF
* web.xml (required if you use servlets)
* classes
* lib
* wai-servlet-app.jar
* The web.xml for the default wai servlet could be
```xml
wai-servlet-test
wai-servlet
network.wai.servlet.DefaultWaiServlet
wai-servlet
/
```
* You have to place the jar or jars generated by etlas in WEB-INF/lib and package the structure in a war file (using jar tool f.e.)
* With the war file you can deploy your wai application in a servlet container:
* tomcat: https://tomcat.apache.org/tomcat-8.0-doc/deployer-howto.html
* the easier way is to place the war file in $TOMCAT_INSTALL_DIR$/webapps
* jetty: https://www.eclipse.org/jetty/documentation/9.4.x/configuring-deployment.html