一个网络连接（通常是 HTTP）从建立到返回的过程中有可能会出现很多种异常情况，比如 DNS 解析错误，比如服务器超时，比如 404……
我的问题：
- 在 Ruby 中有哪些异常是跟网络连接有关的？我 Google 到这篇文章，作者列出的是
SocketError, Timeout::Error, ActiveResource::TimeoutError, Errno::ECONNREFUSED, Errno::EHOSTDOWN, Errno::EHOSTUNREACH，显然这并不是完整的列表…… - 下面两种写法哪种更好？
捕获所有异常
require 'net/http'
begin
content = Net::HTTP.get_response(URI('http://ruby-china.org')).body
rescue Exception
content = ''
end
捕获每一个指定的异常（不完全的列表）
require 'net/http'
begin
content = Net::HTTP.get_response(URI('http://ruby-china.org')).body
rescue SocketError, Errno::ETIMEDOUT, Errno::ECONNREFUSED,
Errno::EHOSTDOWN, Errno::EHOSTUNREACH
content = ''
end
vkill
#3
2012年03月05日
@iwinux 这个得看你用的哪个 gem 吧？gem 中是否很详细的定义这些 error
比如 net/http net/http.rb 里 require 了 net/protocol 和 openssl 那么就可以在这两个文件里查找定义的 error 类了 如
#http.rb 里的
class HTTPBadResponse < StandardError; end
class HTTPHeaderSyntaxError < StandardError; end
#protocol.rb 里的
class ProtocolError < StandardError; end
class ProtoSyntaxError < ProtocolError; end
class ProtoFatalError < ProtocolError; end
class ProtoUnknownError < ProtocolError; end
class ProtoServerError < ProtocolError; end
class ProtoAuthError < ProtocolError; end
class ProtoCommandError < ProtocolError; end
class ProtoRetriableError < ProtocolError; end
ProtocRetryError = ProtoRetriableError
当然还有 openssl 的，自己查下了
vkill
#4
2012年03月05日
@iwinux 另外 404 500 是 response 错误哈，也可以看官方文档
HTTPResponse
HTTPUnknownResponse
HTTPInformation # 1xx
HTTPContinue # 100
HTTPSwitchProtocol # 101
HTTPSuccess # 2xx
HTTPOK # 200
HTTPCreated # 201
HTTPAccepted # 202
HTTPNonAuthoritativeInformation # 203
HTTPNoContent # 204
HTTPResetContent # 205
HTTPPartialContent # 206
HTTPRedirection # 3xx
HTTPMultipleChoice # 300
HTTPMovedPermanently # 301
HTTPFound # 302
HTTPSeeOther # 303
HTTPNotModified # 304
HTTPUseProxy # 305
HTTPTemporaryRedirect # 307
HTTPClientError # 4xx
HTTPBadRequest # 400
HTTPUnauthorized # 401
HTTPPaymentRequired # 402
HTTPForbidden # 403
HTTPNotFound # 404
HTTPMethodNotAllowed # 405
HTTPNotAcceptable # 406
HTTPProxyAuthenticationRequired # 407
HTTPRequestTimeOut # 408
HTTPConflict # 409
HTTPGone # 410
HTTPLengthRequired # 411
HTTPPreconditionFailed # 412
HTTPRequestEntityTooLarge # 413
HTTPRequestURITooLong # 414
HTTPUnsupportedMediaType # 415
HTTPRequestedRangeNotSatisfiable # 416
HTTPExpectationFailed # 417
HTTPServerError # 5xx
HTTPInternalServerError # 500
HTTPNotImplemented # 501
HTTPBadGateway # 502
HTTPServiceUnavailable # 503
HTTPGatewayTimeOut # 504
HTTPVersionNotSupported # 505