Question I have is, does Ruby on Rails have a function similar to:
我的问题是，Ruby on Rails是否具有类似于以下功能：
file_content_type = MIME::Types.type_for(file).first.content_type
that will return the file extension or postfix for a specific mime type? So if I pass in 'image/jpeg' the function will return 'jpg'
这将返回特定mime类型的文件扩展名或后缀？所以，如果我传入'image / jpeg'，该函数将返回'jpg'
Looking for a cleaner way to code than having to write a case statement that does the same job.
寻找一种更清晰的代码编写方式，而不是编写执行相同工作的case语句。
2 个解决方案
#1
34
Rack::Mime has this ability (and Rack is a dependency of Rails):
Rack :: Mime有这种能力（而Rack是Rails的依赖）：
require 'rack/mime'
Rack::Mime::MIME_TYPES.invert['image/jpeg'] #=> ".jpg"
You may wish to memoize the inverted hash if you’re going to do the lookup often, as it’s not an inexpensive operation.
如果您要经常进行查找，您可能希望记住反向哈希，因为它不是一个便宜的操作。
#2
0
A better more up to date answer, since I found this googling.
一个更好的更新答案，因为我发现这个谷歌搜索。
Mime::Type.lookup('image/jpeg').symbol.to_s
# => "jpg"
#1
34
Rack::Mime has this ability (and Rack is a dependency of Rails):
Rack :: Mime有这种能力（而Rack是Rails的依赖）：
require 'rack/mime'
Rack::Mime::MIME_TYPES.invert['image/jpeg'] #=> ".jpg"
You may wish to memoize the inverted hash if you’re going to do the lookup often, as it’s not an inexpensive operation.
如果您要经常进行查找，您可能希望记住反向哈希，因为它不是一个便宜的操作。
#2
0
A better more up to date answer, since I found this googling.
一个更好的更新答案，因为我发现这个谷歌搜索。
Mime::Type.lookup('image/jpeg').symbol.to_s
# => "jpg"