在Haskell中解析JSON字符串

I'm working on simple Haskell programme that fetches a JSON string from a server, parses it, and does something with the data. The specifics are not really pertinent for the moment, the trouble I'm having is with parsing the JSON that is returned.

我正在研究简单的Haskell程序，该程序从服务器获取JSON字符串，解析它，并对数据执行某些操作。目前的细节并不是真正相关，我遇到的麻烦是解析返回的JSON。

I get the JSON string back from the server as an IO String type and can't seem to figure out how to parse that to a JSON object.

我从服务器返回JSON字符串作为IO String类型，似乎无法弄清楚如何将其解析为JSON对象。

Any help would be much appreciated :)

任何帮助将非常感激：）

Here is my code thus far.

到目前为止，这是我的代码。

import Data.Aeson
import Network.HTTP

main = do
    src <- openURL "http://www.reddit.com/user/chrissalij/about.json"
    -- Json parsing code goes here

openURL url = getResponseBody =<< simpleHTTP (getRequest url)

Note: I'm using Data.Aeson in the example as that is what seems to be recommended, however I'd be more than willing to use another library.

注意：我在示例中使用的是Data.Aeson，因为这似乎是推荐的，但是我更愿意使用另一个库。

Also any and all of this code can be changed. If getting the

此外，任何和所有代码都可以更改。如果得到了

1 个解决方案

#1

Data.Aeson is designed to be used with Attoparsec, so it only gives you a Parser that you must then use with Attoparsec. Also, Attoparsec prefers to work on ByteString, so you have to alter the way the request is made slightly to get a ByteString result instead of a String.

Data.Aeson旨在与Attoparsec一起使用，因此它只为您提供一个Parser，然后您必须使用Attoparsec。此外，Attoparsec更喜欢使用ByteString，因此您必须稍微改变请求的方式以获取ByteString结果而不是String。

This seems to work:

这似乎有效：

import Data.Aeson
import Data.Attoparsec
import Data.ByteString
import Data.Maybe
import Network.HTTP
import Network.URI

main = do
    src <- openURL "http://www.reddit.com/user/chrissalij/about.json"
    print $ parse json src

openURL :: String -> IO ByteString
openURL url = getResponseBody =<< simpleHTTP (mkRequest GET (fromJust $ parseURI url))

Here I've just parsed the JSON as a plain Value, but you'll probably want to create your own data type and write a FromJSON instance for it to handle the conversion neatly.

在这里，我刚刚将JSON解析为普通值，但您可能希望创建自己的数据类型并为其编写FromJSON实例以便整齐地处理转换。

#1