Ruby RSS::Parser.to_s 默默失败？
我正在使用 Ruby 1.8.7 的 RSS::Parser，它是 stdlib 的一部分。我是红宝石新手。
我想解析 RSS 提要，对数据进行一些更改，然后将其输出（作为 RSS）。
文档说我可以使用“#to_s”，但是它似乎适用于某些提要，但不适用于其他提要。
这有效：
#!/usr/bin/ruby -w
require 'rss'
require 'net/http'
url = 'http://news.ycombinator.com/rss'
feed = Net::HTTP.get_response(URI.parse(url)).body
rss = RSS::Parser.parse(feed, false, true)
# Here I would make some changes to the RSS, but right now I'm not.
p rss.to_s
返回预期输出：XML 文本。
失败：
#!/usr/bin/ruby -w
require 'rss'
require 'net/http'
url = 'http://feeds.feedburner.com/devourfeed'
feed = Net::HTTP.get_response(URI.parse(url)).body
rss = RSS::Parser.parse(feed, false, true)
# Here I would make some changes to the RSS, but right now I'm not.
p rss.to_s
不返回任何内容（空引号）。
然而，如果我将最后一行更改为：
p rss
我可以看到该对象填充了所有提要数据。这是 to_s 方法失败了。
- 为什么？
- 如何获得某种错误输出来调试这样的问题？
I'm using Ruby 1.8.7's RSS::Parser, part of stdlib. I'm new to Ruby.
I want to parse an RSS feed, make some changes to the data, then output it (as RSS).
The docs say I can use '#to_s', but and it seems to work with some feeds, but not others.
This works:
#!/usr/bin/ruby -w
require 'rss'
require 'net/http'
url = 'http://news.ycombinator.com/rss'
feed = Net::HTTP.get_response(URI.parse(url)).body
rss = RSS::Parser.parse(feed, false, true)
# Here I would make some changes to the RSS, but right now I'm not.
p rss.to_s
Returns expected output: XML text.
This fails:
#!/usr/bin/ruby -w
require 'rss'
require 'net/http'
url = 'http://feeds.feedburner.com/devourfeed'
feed = Net::HTTP.get_response(URI.parse(url)).body
rss = RSS::Parser.parse(feed, false, true)
# Here I would make some changes to the RSS, but right now I'm not.
p rss.to_s
Returns nothing (empty quotes).
And yet, if I change the last line to:
p rss
I can see that the object is filled with all of the feed data. It's the to_s method that fails.
- Why?
- How can I get some kind of error output to debug a problem like this?
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据我所知，问题不在
to_s中，而是在解析器本身中。单步执行 parser.rb 代码显示没有返回任何内容，因此to_s返回空字符串是有效的。我建议查看类似 Feedzirra 的内容。
另外，仅供参考，请查看 Ruby 的
Open::URI< /code>模块，用于轻松检索网络资产，例如提要。 Open-URI 很简单，但足以满足大多数任务。 Net::HTTP 是较低级别的，这将需要您键入更多代码来替换 Open-URI 的功能。From what I can tell, the problem isn't in
to_s, it's in the parser itself. Stepping way into the parser.rb code showed nothing being returned, soto_sreturning an empty string is valid.I'd recommend looking at something like Feedzirra.
Also, as a FYI, take a look at Ruby's
Open::URImodule for easy retrieval of web assets, like feeds. Open-URI is simple but adequate for most tasks. Net::HTTP is lower level, which will require you to type a lot more code to replace the functionality of Open-URI.我也遇到了同样的问题，所以我开始调试代码。我认为 ruby rss 有太多必需的元素。频道需要有“标题、链接、描述”，缺少其中一项就会失败。
上面示例中的第二个提要缺少描述，这将使 to_s 失败...
我相信这是一个错误，但我真的不理解代码，几乎不懂 ruby，所以谁知道呢。对我来说，即使缺少某些元素，to_s 也会尽力而为，这似乎很自然。
无论哪种方式
rss.channel.description="something"
rss.to_s
将“工作”
问题在于 def have_required_elements?
或者在
self.class::模型
I had the same problem, so I started debugging the code. I think the ruby rss has a few too many required elements. The channel need to have "title, link, description", if one is missing to_s will fail.
The second feed in the example above is missing the description, which will make the to_s fail...
I believe this is a bug, but I really don't understand the code and barely ruby so who knows. It would seem natural to me that to_s would try its best even if some elements are missing.
Either way
rss.channel.description="something"
rss.to_s
will "work"
The problem lies in def have_required_elements?
Or in the
self.class::MODELS