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https://github.com/caneroj1/filter-logger
Filterable request logging as wai middleware
https://github.com/caneroj1/filter-logger
haskell http logging
Last synced: 24 days ago
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Filterable request logging as wai middleware
- Host: GitHub
- URL: https://github.com/caneroj1/filter-logger
- Owner: caneroj1
- License: mit
- Created: 2017-07-11T23:52:53.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2017-07-16T15:47:39.000Z (over 7 years ago)
- Last Synced: 2024-04-25T05:42:36.625Z (7 months ago)
- Topics: haskell, http, logging
- Language: Haskell
- Size: 37.1 KB
- Stars: 7
- Watchers: 3
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# filter-logger
[Hackage](https://hackage.haskell.org/package/filter-logger#readme)
[](https://travis-ci.org/caneroj1/filter-logger)
Filterable request logging as a wai middleware. Change what data is logged and when.
## Usage
Here is one example from the **examples/password** directory where we use the filter logger to implement password filtering. The example uses `scotty` for our web server, and we use the `logShowJSON` and `logFilterJSON` helper functions to help us create our instances.
### Password Filtering
```haskell
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
module Main where
import Data.Aeson
import GHC.Generics
import Network.Wai.Middleware.FilterLogger
import Web.Scotty
data LoginRequest = LoginRequest {
username :: String
, password :: String
} deriving (Generic)
instance FromJSON LoginRequest where
instance ToJSON LoginRequest where
instance LogShowable LoginRequest where
logShow = logShowJSON
instance LogFilterable LoginRequest where
prep = logFilterJSON
instance Loggable LoginRequest where
main :: IO ()
main = scotty 3000 $ do
middleware filterPasswords
post "/" $ text "SUCCESS"
filterPasswords =
mkDefaultFilterLogger hidePasswords
where hidePasswords r@LoginRequest{..} = Just r {password = "*****"}
```
Sending a POST request to localhost:3000 with a body like
```
{
"username": "test-username",
"password": "myPassw0rd123"
}
```
will result in a log message like
```
11/Jul/2017:21:48:20 -0400
200 - OK
0.03ms
{
"username": "test-username",
"password": "*****"
}
```
### Chaining Filters
Here is a rather contrived example showing that you can chain these filters together easily and do all sorts of filtering.
```haskell
{-# LANGUAGE OverloadedStrings #-}
module Main where
import Control.Monad
import qualified Data.ByteString as BS (elem, length)
import Data.Char
import Data.Word
import Network.Wai.Middleware.FilterLogger
import Web.Scotty
main :: IO ()
main = scotty 3000 $ do
middleware filteringMiddleware
post "/" $ text "SUCCESS"
filteringMiddleware =
mkDefaultFilterLogger (keepShortBodies >=> containing 'c')
where keepShortBodies bs
| BS.length bs < 10 = Just bs
| otherwise = Nothing
containing c bs
| BS.elem (fromIntegral $ ord c) bs = Just bs
| otherwise = Nothing
```
Sending a POST request to localhost:3000 with a body like
```
abcdefghi
```
will result in a log message like
```
11/Jul/2017:22:00:59 -0400
200 - OK
0.03ms
abcdefghi
```
If you send a POST request with a body like
```
abcdefghij
```
or
```
abdefghij
```
you won't see anything in the server logs.
## Customization
Customizing the log filtering middleware can be done with the `FilterOptions` type. It supports two options currently:
* Detailed logging: Includes the request duration in milliseconds and the response body size. `True` by default.
* Log when the request body is empty: Boolean value indicating whether or not to create log messages when there is no request body. `True` by default.