Facing issue while writing data into a file in python script

Question

I have to write 7231 bytes into a file using python script. In a client-server program, my python script act like client and it received 7231 bytes from server. If I check in TCP-Dump, its shows complete data. But when I try to write into a file; I am missing the content.

My script:

   def SendOnce(self, req='/gpsData=1',method="GET"):
       conn = httplib.HTTPConnection(self.proxy)
       self.Logresponse("\nConnection Open\n<br />")
       conn.request(method,req)
       Log="\nRequest Send: %s\n<br \>\n" %req
       self.Logresponse(Log)
       response = conn.getresponse()
       Log = "\nResponse Code: %s\n<br \>\n" %response.status
       self.Logresponse(Log)
       Log = "\nSarav -- Get Header: %s \n version= %s <br \>\n"           %(response.msg,response.version)
       self.Logresponse(Log)
       if (response.status==200):
           Log = response.read()
           self.Logresponse(Log)
       conn.close()
       self.Logresponse("\nConnection Close\n<br \>")
       return response

this "self.Logresponse(Log)" is writing into file. If i receive 1023 bytes, its writing full content into that. Please help me out how to write complete data. Note: I am writing Hexa Format data.

Please use the code tags (the {} icon) to format your code. Otherwise we have to guess at its structure since indentation is semantically significant. — NPE
– NPE, Commented Dec 1, 2011 at 12:37
Probably we will need to see Logresponse to help with this problem. — mtrw
– mtrw, Commented Dec 1, 2011 at 12:41
Are you flushing the stream after the write? Please post the code for def Logresponse too. — chown
– chown, Commented Dec 1, 2011 at 12:42
@Wooble I think the question is rather, 'How long has it been since 7K was a "huge" amount of data?' ;) — Karl Knechtel
– Karl Knechtel, Commented Dec 1, 2011 at 12:54

Community · Accepted Answer · 2017-05-23 11:44:40Z

3

First of all, 7231 bytes is not exactly huge...

With the limited info you gave, I would guess that you might have forgotten to take the OS's write buffer into account. You probably try to read the file before all the content was written to it.

Python generally uses the system's standard buffer (you can change that). You can decrease that buffer, or force a flush yourself.

edited May 23, 2017 at 11:44

CommunityBot

11 silver badge

answered Dec 1, 2011 at 12:51

rwos

1,8911 gold badge16 silver badges18 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Basilevs Over a year ago

Using context management on files is also a good idea.

user1042979 Over a year ago

the Logresponse Code: { def Logresponse(self,response): message=response logfile=open(".//log//BSRLog.html",'a') logfile.write(message) logfile.close() }

rwos Over a year ago

Hm, not good. The close() already does an implicit flush(). This does not mean that the data must be actually physically on the disk - but the next open() to read should in fact return the whole thing... Strange. Could you try to open with bufsize set to 0 in Logresponse? i.e. open(".//log//BSRLog.html",'a', 0)

user1042979 Over a year ago

@rwos: Thanks for response. Yes! i did the same. but getting the same result. Data is not written completely in BSRLog.html file. Actually the file size shows 7K bytes but still half of the data content i am missing.

ondra · Accepted Answer · 2011-12-01 13:42:07Z

0

I'm just guessing, it might be that the .read() function doesn't return all data in one chunk; can you try to modify the inner part like this:

if (response.status==200):
     while 1:
         Log = response.read()
         if not Log:
             break
         self.Logresponse(Log)

answered Dec 1, 2011 at 13:42

ondra

9,3711 gold badge27 silver badges36 bronze badges

2 Comments

user1042979 Over a year ago

This above code is giving syntax error. Where to fit this break statement. Its says syntax err: break is out of loop

ondra Over a year ago

Check indentation; the 'break' breaks out of the while loop; this is correct code.

Collectives™ on Stack Overflow

Facing issue while writing data into a file in python script

2 Answers 2

4 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related