try:
r = requests.get(url, params={'s': thing})
except requests.ConnectionError, e:
print e #should I also sys.exit(1) after this?
这是对的吗?有没有更好的方法来构建它?这会涵盖我的所有基础吗?
答案 0 :(得分:572)
查看请求exception docs。简而言之:
如果出现网络问题(例如DNS失败,拒绝连接等),请求将引发
ConnectionError
例外。如果罕见的无效HTTP响应,请求将引发
HTTPError
例外。如果请求超时,则会引发
Timeout
异常。如果请求超出配置的最大重定向数,则会引发
TooManyRedirects
异常。请求明确提出的所有异常都来自
requests.exceptions.RequestException
。
要回答您的问题,您展示的内容将不涵盖您的所有基础。您只能捕获与连接相关的错误,而不是那些超时的错误。
捕获异常时该怎么做才能完全取决于脚本/程序的设计。退出是否可以接受?你能继续再试一次吗?如果错误是灾难性的并且您无法继续,那么是的,对sys.exit()
的调用是有序的。
您可以捕获基类异常,它将处理所有情况:
try:
r = requests.get(url, params={'s': thing})
except requests.exceptions.RequestException as e: # This is the correct syntax
print e
sys.exit(1)
或者你可以单独捕捉它们并做不同的事情。
try:
r = requests.get(url, params={'s': thing})
except requests.exceptions.Timeout:
# Maybe set up for a retry, or continue in a retry loop
except requests.exceptions.TooManyRedirects:
# Tell the user their URL was bad and try a different one
except requests.exceptions.RequestException as e:
# catastrophic error. bail.
print e
sys.exit(1)
正如Christian所指出的那样:
如果您希望http错误(例如401 Unauthorized)引发异常,您可以致电
Response.raise_for_status
。如果响应是http错误,那将引发HTTPError
。
一个例子:
try:
r = requests.get('http://www.google.com/nothere')
r.raise_for_status()
except requests.exceptions.HTTPError as err:
print err
sys.exit(1)
将打印:
404 Client Error: Not Found for url: http://www.google.com/nothere
答案 1 :(得分:43)
另外一个明确的建议。最好从特定的错误到一般的错误堆栈,以获得所需的错误,因此特定的错误不会被普通错误掩盖。
url='http://www.google.com/blahblah'
try:
r = requests.get(url,timeout=3)
r.raise_for_status()
except requests.exceptions.HTTPError as errh:
print ("Http Error:",errh)
except requests.exceptions.ConnectionError as errc:
print ("Error Connecting:",errc)
except requests.exceptions.Timeout as errt:
print ("Timeout Error:",errt)
except requests.exceptions.RequestException as err:
print ("OOps: Something Else",err)
Http Error: 404 Client Error: Not Found for url: http://www.google.com/blahblah
VS
url='http://www.google.com/blahblah'
try:
r = requests.get(url,timeout=3)
r.raise_for_status()
except requests.exceptions.RequestException as err:
print ("OOps: Something Else",err)
except requests.exceptions.HTTPError as errh:
print ("Http Error:",errh)
except requests.exceptions.ConnectionError as errc:
print ("Error Connecting:",errc)
except requests.exceptions.Timeout as errt:
print ("Timeout Error:",errt)
OOps: Something Else 404 Client Error: Not Found for url: http://www.google.com/blahblah
答案 2 :(得分:2)
异常对象还包含原始响应e.response
,如果需要查看服务器响应中的错误正文,则该异常很有用。例如:
try:
r = requests.post('somerestapi.com/post-here', data={'birthday': '9/9/3999'})
r.raise_for_status()
except requests.exceptions.HTTPError as e:
print (e.response.text)