Re: [protobuf] fails to parse from string
hmmm, i have to use UDP in my case, TCP is not an option. On Wed, Nov 10, 2010 at 2:40 PM, Evan Jones wrote: > On Nov 10, 2010, at 14:13 , Brad Lira wrote: >> >> yes it was the null character, on the server side when copying buffer >> into string, i had add 1 to the >> size of the buffer (i guess for the null), then the parsing was ok >> with no error. > > Just adding 1 is still probably not correct. You have similar incorrect code > on the receive side: > >> recvfrom(socket, buf, ) >> mystr.assign(buf, strlen(buf)); > > > strlen(buf) is not going to give you the right thing. You should be using > the return value from recvfrom(), which gives you the number of bytes that > were read from the network. > > Note: If you are using UDP, it will end up not working as soon as you have a > message which is bigger than either your buffer, or the maximum UDP packet > size, whichever comes first. > > Evan > > -- > Evan Jones > http://evanjones.ca/ > > -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
Re: [protobuf] fails to parse from string
On Nov 10, 2010, at 14:13 , Brad Lira wrote: yes it was the null character, on the server side when copying buffer into string, i had add 1 to the size of the buffer (i guess for the null), then the parsing was ok with no error. Just adding 1 is still probably not correct. You have similar incorrect code on the receive side: recvfrom(socket, buf, ) mystr.assign(buf, strlen(buf)); strlen(buf) is not going to give you the right thing. You should be using the return value from recvfrom(), which gives you the number of bytes that were read from the network. Note: If you are using UDP, it will end up not working as soon as you have a message which is bigger than either your buffer, or the maximum UDP packet size, whichever comes first. Evan -- Evan Jones http://evanjones.ca/ -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
Re: [protobuf] fails to parse from string
On Wed, Nov 10, 2010 at 08:23, Brad Lira wrote:
> client side:
>
> address_book.SerializeToString(&mystr)
> strncpy(buf, mystr.c_str(), strlen(mystr.c_str()));
This is an error - you only copy to the first \0 byte (strlen looks
for a nul-terminated string) -- however, the string contains binary
data.
And: why do you copy the data in the first place to some buffer ? This
is an additional (potentially expensive) memory copy; why not use the
buffer directly from the string ?
sendto(socket, mystr.data(), mystr.size() ...)
> sendto(socket, buf, )
>
> server side:
>
> recvfrom(socket, buf, )
> mystr.assign(buf, strlen(buf));
>
> if (address_book.ParseFromString(mystr) == false)
> {
> print "deserialization failed"
> }
>
> I get deserialization failed all the time, but get the message correctly
> though.
>
> Maybe this method is not the right way to send string across socket.
> I tried using SerializeToFileDescriptor(socket), that worked on the
> client side, but on the server side, i never get the message with UDP sockets.
> is there a better way of sending data across network?
>
> thanks,
>
>
> On Tue, Nov 9, 2010 at 5:43 PM, Kenton Varda wrote:
>> It sounds like you probably have extra bytes at the end of mystr which are
>> not part of the protobuf. The parser parses everything before those bytes
>> just fine, but then chokes when it gets to the bytes it doesn't recognize.
>> Please make sure you only pass in the exact bytes which came out of the
>> serializer at the other end, no more, no less.
>>
>> On Tue, Nov 9, 2010 at 1:11 PM, Brad Lira wrote:
>>>
>>> I have a c++ client/server application that sends messages using
>>> protocol buffers, however, at the server side, when i call
>>>
>>> address_book.ParseFromString(mystr)
>>>
>>> it returns false, but it actually gets the message correctly from
>>> client side, so i am not sure why it thinks that parsing has failed.
>>> any ideas?
>>>
>>> thanks,
>>> brad
>>>
>>> --
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>>>
>>
>>
>
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Re: [protobuf] fails to parse from string
thanks, yes it was the null character, on the server side when copying buffer into string, i had add 1 to the size of the buffer (i guess for the null), then the parsing was ok with no error. On Wed, Nov 10, 2010 at 1:42 PM, Evan Jones wrote: > Brad Lira wrote: >> >> address_book.SerializeToString(&mystr) >> strncpy(buf, mystr.c_str(), strlen(mystr.c_str())); > > strlen will return a shorter length than the real length, due to null > characters. Use mystr.size() > > > >> Maybe this method is not the right way to send string across socket. >> I tried using SerializeToFileDescriptor(socket), that worked on the >> client side, but on the server side, i never get the message with UDP >> sockets. >> is there a better way of sending data across network? > > You probably want to use TCP sockets, since it provides retransmissions for > you. Also, you'll need to prepend a length. See: > > http://code.google.com/apis/protocolbuffers/docs/techniques.html#streaming > > > Or search the group archives for threads such as: > > http://groups.google.com/group/protobuf/browse_thread/thread/3af587ab16132a3f > > > Good luck, > > Evan > > -- > Evan Jones > http://evanjones.ca/ > -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
Re: [protobuf] fails to parse from string
Brad Lira wrote: address_book.SerializeToString(&mystr) strncpy(buf, mystr.c_str(), strlen(mystr.c_str())); strlen will return a shorter length than the real length, due to null characters. Use mystr.size() Maybe this method is not the right way to send string across socket. I tried using SerializeToFileDescriptor(socket), that worked on the client side, but on the server side, i never get the message with UDP sockets. is there a better way of sending data across network? You probably want to use TCP sockets, since it provides retransmissions for you. Also, you'll need to prepend a length. See: http://code.google.com/apis/protocolbuffers/docs/techniques.html#streaming Or search the group archives for threads such as: http://groups.google.com/group/protobuf/browse_thread/thread/3af587ab16132a3f Good luck, Evan -- Evan Jones http://evanjones.ca/ -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
Re: [protobuf] fails to parse from string
client side:
address_book.SerializeToString(&mystr)
strncpy(buf, mystr.c_str(), strlen(mystr.c_str()));
sendto(socket, buf, )
server side:
recvfrom(socket, buf, )
mystr.assign(buf, strlen(buf));
if (address_book.ParseFromString(mystr) == false)
{
print "deserialization failed"
}
I get deserialization failed all the time, but get the message correctly though.
Maybe this method is not the right way to send string across socket.
I tried using SerializeToFileDescriptor(socket), that worked on the
client side, but on the server side, i never get the message with UDP sockets.
is there a better way of sending data across network?
thanks,
On Tue, Nov 9, 2010 at 5:43 PM, Kenton Varda wrote:
> It sounds like you probably have extra bytes at the end of mystr which are
> not part of the protobuf. The parser parses everything before those bytes
> just fine, but then chokes when it gets to the bytes it doesn't recognize.
> Please make sure you only pass in the exact bytes which came out of the
> serializer at the other end, no more, no less.
>
> On Tue, Nov 9, 2010 at 1:11 PM, Brad Lira wrote:
>>
>> I have a c++ client/server application that sends messages using
>> protocol buffers, however, at the server side, when i call
>>
>> address_book.ParseFromString(mystr)
>>
>> it returns false, but it actually gets the message correctly from
>> client side, so i am not sure why it thinks that parsing has failed.
>> any ideas?
>>
>> thanks,
>> brad
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "Protocol Buffers" group.
>> To post to this group, send email to proto...@googlegroups.com.
>> To unsubscribe from this group, send email to
>> protobuf+unsubscr...@googlegroups.com.
>> For more options, visit this group at
>> http://groups.google.com/group/protobuf?hl=en.
>>
>
>
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Re: [protobuf] fails to parse from string
It sounds like you probably have extra bytes at the end of mystr which are not part of the protobuf. The parser parses everything before those bytes just fine, but then chokes when it gets to the bytes it doesn't recognize. Please make sure you only pass in the exact bytes which came out of the serializer at the other end, no more, no less. On Tue, Nov 9, 2010 at 1:11 PM, Brad Lira wrote: > I have a c++ client/server application that sends messages using > protocol buffers, however, at the server side, when i call > > address_book.ParseFromString(mystr) > > it returns false, but it actually gets the message correctly from > client side, so i am not sure why it thinks that parsing has failed. > any ideas? > > thanks, > brad > > -- > You received this message because you are subscribed to the Google Groups > "Protocol Buffers" group. > To post to this group, send email to proto...@googlegroups.com. > To unsubscribe from this group, send email to > protobuf+unsubscr...@googlegroups.com > . > For more options, visit this group at > http://groups.google.com/group/protobuf?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
Re: [protobuf] fails to parse from string
On Nov 9, 2010, at 16:11 , Brad Lira wrote: it returns false, but it actually gets the message correctly from client side, so i am not sure why it thinks that parsing has failed. any ideas? How are you putting data into mystr? Protocol buffers contain null bytes, so you must pass both a char* and a length: mystr.assign(data, length); Evan -- Evan Jones http://evanjones.ca/ -- You received this message because you are subscribed to the Google Groups "Protocol Buffers" group. To post to this group, send email to proto...@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
