用Ruby重写字符串中的字符 [英] Unescaping characters in a string with Ruby

问题描述

给出一个以下格式的字符串（Posterous API以此格式返回帖子）：

  s =\ \\\
  

如何将其转换为实际的ascii字符，以便 s =< p>？

在OSX上，我成功使用了 Iconv .iconv（'ascii'，'java'，s）但是一旦部署到Heroku，我会收到一个 Iconv :: IllegalSequence exception。我猜，Heroku部署的系统不支持 java 编码器。

---

我正在使用 HTTParty 向Posterous API发出请求。如果我使用卷曲来做出相同的请求，那么我不要获得双斜杠。

从HTTParty github页面：

将JSON和XML自动解析为
基于响应的ruby哈希
content-type

Posterous API返回JSON（无双斜杠）和HTTParty的JSON解析正在插入双斜杠。

---

以下是我使用HTTParty发出请求的一个简单示例。

  class Posterous 
 include HTTParty 
 base_urihttp://www.posterous.com/api / 2
 basic_authusername，password
格式：json 
 def get_posts 
 response = Posterous.get（/ users / me / sites / 9876 / posts& api_token = 1234）
＃snip，see below ... 
 end 
 end 
  

将明显的信息（用户名，密码，site_id，api_token）替换为有效值。

在剪辑点， response.body 包含一个Ruby字符串，我s的JSON格式和 response.parsed_response 包含一个Ruby哈希对象，它通过解析来自Posterous API的JSON响应创建的。

在这两种情况下，诸如 \\\< 的unicode序列已更改为 \\003C

解决方案

我遇到了这个确切的问题。 HTTParty使用的json解析器（Crack gem）中存在一个错误 - 基本上它对Unicode序列使用区分大小写的正则表达式，因此，由于Posterous将A-F代替为-f，所以Crack不会对其进行转义。我提交了一个拉动请求来解决这个问题。

在此期间，HTTParty很好地让您指定替代解析器，以便您可以执行 :: JSON.parse 绕过破解完全如下所示：

  class JsonParser< HTTParty :: Parser 
 def json 
 :: JSON.parse（body）
 end 
 end 
 
 class Posterous 
 include HTTParty 
 parser :: JsonParser 
 
＃.... 
 end 
  

Given a string in the following format (the Posterous API returns posts in this format):

s="\\u003Cp\\u003E"

How can I convert it to the actual ascii characters such that s="<p>"?

On OSX, I successfully used Iconv.iconv('ascii', 'java', s) but once deployed to Heroku, I receive an Iconv::IllegalSequence exception. I'm guessing that the system Heroku deploys to does't support the java encoder.

---

I am using HTTParty to make a request to the Posterous API. If I use curl to make the same request then I do not get the double slashes.

From HTTParty github page:

Automatic parsing of JSON and XML into ruby hashes based on response content-type

The Posterous API returns JSON (no double slashes) and HTTParty's JSON parsing is inserting the double slash.

---

Here is a simple example of the way I am using HTTParty to make the request.

class Posterous
  include HTTParty
  base_uri "http://www.posterous.com/api/2"
  basic_auth "username", "password"
  format :json
  def get_posts
    response = Posterous.get("/users/me/sites/9876/posts&api_token=1234")
    # snip, see below...
  end
end

With the obvious information (username, password, site_id, api_token) replaced with valid values.

At the point of snip, response.body contains a Ruby string that is in JSON format and response.parsed_response contains a Ruby hash object which HTTParty created by parsing the JSON response from the Posterous API.

In both cases the unicode sequences such as \u003C have been changed to \\u003C.

解决方案

I ran into this exact problem the other day. There is a bug in the json parser that HTTParty uses (Crack gem) - basically it uses a case-sensitive regexp for the Unicode sequences, so because Posterous puts out A-F instead of a-f, Crack isn't unescaping them. I submitted a pull request to fix this.

In the meantime HTTParty nicely lets you specify alternate parsers so you can do ::JSON.parse bypassing Crack entirely like this:

class JsonParser < HTTParty::Parser
  def json
    ::JSON.parse(body)
  end
end

class Posterous
   include HTTParty
   parser ::JsonParser

   #....
end

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