This library is a simple C++ wrapper for the C library http-parser[1]
(This code was derived from the HTTP parser code in NGINX). http-parser is
a simple HTTP streaming parser (for those of you familiar with XML, it works
much like a SAX parser). It knows nothing of sockets or streams. You feed it
data and it invokes registered callbacks to notify of available data. Because
http-parser operates at the very lowest level, it does not buffer data or
allocate memory dynamically. This library attempts to make that library easily
usable by C++ programs by interpreting those callbacks and buffering data where
needed.
http-parser itself has no dependencies and compiles with C++ compilers.
httpcxx uses only standard library facilities (namely std::string and
std::map) and introduces no additional dependencies.
The code should compile as is under a standard-compliant C++03 implementation.
Memory allocation policy
A good memory allocation policy is important in server programs, which typically
run for a long time and suffer from memory fragmentation. httpcxx does its
best to avoid repeated allocation, but it needs a little help on your part.
http::Request and http::Response parser object allocate memory as
required because they buffer different parts of the incoming HTTP
request/response in std::string instances. However, they are implemented
carefully as to use the growing property of std::string[4] to their
advantage. In particular, you may re-use http::Request and
http::Response parser objects for parsing multiple request/response objects
using their .clear() method. This method marks all header lengths as 0 but
keeps the instances as well as the map. All this ensures that parsers avoid
repeated memory allocation.
std::string instances keep the allocated memory buffer even when you
resize them such that their length decreases. In particular,
std::string::clear() marks the string length as 0 but keeps the allocated
buffer.
Samples / demos
Check out the sample programs in the demo/ subfolder.
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