10. HTTP Library (internal)
===========================

The HTTP Library is split up in three parts:

* httpnet.cpp / Network Processing (Tests)
* httpparser.cpp / HTTP Parsing (Header, Payload)
* httpgen.cpp / HTTP Generating (Header)

10.1. Compiling / Linking
-------------------------

The HTTPLib library gets linked shared because it wil be used by multiple applications (e.g. test).

10.2. Program Logic (httpparser.cpp)
------------------------------------

Features:

* GET Requests (without Content-Length header)
* POST Requests (with Content-Length header and bytes[size] after "\n\r" end marker
* Multiple HTTP "messages" in one TCP packet
* Fragmented (partial) messages without end marker "\n\r" (GET) or "Content-Length" (POST)

10.2.1. appendBuffer()
~~~~~~~~~~~~~~~~~~~~~~

10.2.1.1. Params
^^^^^^^^^^^^^^^^

1. const char* BufferRef
2. const uint16_t BufferSize

10.2.1.2. Processing Logic
^^^^^^^^^^^^^^^^^^^^^^^^^^

The passed buffer data will be apended to _HTTPRequest private member. Afterwards _splitRequests()
method will be called.

10.2.2. _splitRequests()
~~~~~~~~~~~~~~~~~~~~~~~~

1. _SplittedRequests Vector will be cleared
2. All requests inside _HTTPRequest buffer get split by "\n\r" or "\n\r"+Content-Length
3. Single requests will be put inside _SplittedRequests Vector

10.2.3. parseRequestsBasic()
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

10.2.3.1. Params
^^^^^^^^^^^^^^^^

1. SharedMemAddress_t SHMGetRequests
2. const ASRequestHandlerRef_t ASRequestHandlerRef

10.2.3.2. Processing Logic
^^^^^^^^^^^^^^^^^^^^^^^^^^

1. Set SHM Base Address (SHMGetRequests)
2. Foreach _SplittedRequests Vector Element: call _parseBaseProps(&Request, ASRequestHandlerRef)


10.2.4. _parseBaseProps
~~~~~~~~~~~~~~~~~~~~~~~

10.2.4.1. Params
^^^^^^^^^^^^^^^^

1. string& Request
2. const ASRequestHandlerRef_t ASRequestHandlerRef

10.2.4.2. Processing Logic
^^^^^^^^^^^^^^^^^^^^^^^^^^

* Get HTTP Version (HTTP/1.1 or HTTP/1.2)
* Get HTTP Method (GET/POST)
* Get HTTP Payload
* Get HTTP Payload Size (Bytes)

* Check Request Type (StaticFS / Python Script POST AS)

.. code-block:: text

   * On Type SatticFS (SHM Segment #1)

     - Write ClientFD to SHM-StaticFS, increment Pointer Address
     - Write HTTPVersion to SHM-StaticFS, increment Pointer Address
     - Write MsgNr to SHM-StaticFS, increment Pointer Address
     - Write MsgLength to SHM-StaticFS, increment Pointer Address
     - Write MsgPayload to SHM-StaticFS, increment Pointer Address

.. note::

   IPCHandler.hpp and IPCHandler.cpp is used to calculate Shared Memory Adress Offsets.

.. code-block:: text

   * On Type POST AS (SHM Segment #2/Metadata, #3/RequestPayloads)

     // SHM Segment #2
     - Get Next Free AS Index (Check CanRead == 0 && WriteReady == 0)
       - If no Free AS:: add to RequestQueue

     // SHM Segment #2
     - Write ClientFD to SHM-PostAS @AS Index Address
     - Write HTTPVersion to SHM-PostAS @AS Index Address
     - Write HTTPMethod to SHM-PostAS @AS Index Address
     - Write ReqNr to SHM-PostAS @AS Index Address
     - Write ReqPayloadLength to SHM-PostAS @AS Index Address

     //- SHM Segment #3
     - Write ReqPayload to SHM-PostAS @AS Index Address

     // SHM Segment #2
     - Write CanRead = 1 @AS Index Address

.. note::

   IPCHandlerAS.hpp and IPCHandlerAS.cpp is used to calculate Shared Memory Adress Offsets.