Xebra Module Communication Protocol
Basic Communication
For every string message that is to be sent between a module and server, the sender first sends the length of the message ENCODED_MESSAGE_LENGTH and then the message MESSAGE. The max length FRAG_SIZE of a message to be sent is 65536 bytes. If a message is longer, it is divided into fragments. ENCODED_MESSAGE_LENGTH is called ENCODED_ because it also contains a FRAG_FLAG which specifies if the next message is a fragment and has to be assembled to a whole message after receiving.
Let's say the server wants so send a message of size 150'000 bytes to the module. The following would be sent: [65536 FRAG_FLAG=1][Message part 1...][65536 FRAG_FLAG=1][Message part 2....][18928 FRAG_FLAG=0][Message part 3....]
The ENCODED_MESSAGE_LENGTH is constructed as follows: The lenght of the message (integer) is shifted by 1 bit to the left. Then the most right bit is set to FRAG_FLAG.
Request Message
For every request, the module sends a message of the following format to the server:
REQUEST = GET_REQUEST | POST_TABLE_REQUEST | POST_PLAIN_REQUEST; GET_REQUEST = "GET" BODY TABLE_ARGS; POST_TABLE_REQUEST = "POST" BODY TABLE_ARGS; POST_PLAIN_REQUEST = "POST" BODY PLAIN_ARGS; BODY = HEADER HEADERS_IN HEADERS_OUT SUBPROCESS_ENVIRONMENT_VARS; HEADER = " " url " HTTP/1.1"; HEADERS_IN = "#HI#" TABLE_ENTRIES "#E#"; HEADERS_OUT = "#HO#" TABLE_ENTRIES "#E#"; SUBPROCESS_ENVIRONMENT_VARS = "#SE#" TABLE_ENTRIES "#E#"; TABLE_ENTRIES = {"#$#" item_name "#%#" item_value}; TABLE_ARGS = "#A#" {"$" arg_name "=" arg_value} "#E#"; PLAIN_ARGS = "#A#$" plain_args "#E#"; KEY_GET = "GET" KEY_POST = "POST" KEY_HTTP = "HTTP/1.1" KEY_SPACE = " " KEY_HI = "#HI#' KEY_HO = "#HO#' KEY_END = "#E#' KEY_SE = "#SE#' KEY_T_NAME = "#$#" KEY_T_VALUE = "#%#" KEY_ARG = "#A#" KEY_A_NAME = "$" KEY_T_VALUE = "="
Example
GET /demoapplication/reservations.xeb HTTP/1.1#HI##$#Host#%#localhost:55000#$#User-Agent#%#Mozilla/5.0 (X11; U; Linux x86_64; en; rv:1.9.0.11) Gecko/20080528 Epiphany/2.22 Firefox/3.0#$#Accept#%#text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8#$#Accept-Language#%#en-us,en;q=0.5#$#Accept-Encoding#%#gzip,deflate#$#Accept-Charset#%#ISO-8859-1,utf-8;q=0.7,*;q=0.7#$#Keep-Alive#%#300#$#Connection#%#keep-alive#$#Referer#%#http://localhost:55000/demoapplication/contact.xeb#$#Cookie#%#xuuid=E5573216-8AEC-4187-8ECD-0BC38CF36FF0#E##HO##E##SE##E##A##E# POST /demoapplication/login.xeb HTTP/1.1#HI##$#Host#%#localhost:55000#$#User-Agent#%#Mozilla/5.0 (X11; U; Linux x86_64; en; rv:1.9.0.11) Gecko/20080528 Epiphany/2.22 Firefox/3.0#$#Accept#%#text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8#$#Accept-Language#%#en-us,en;q=0.5#$#Accept-Encoding#%#gzip,deflate#$#Accept-Charset#%#ISO-8859-1,utf-8;q=0.7,*;q=0.7#$#Keep-Alive#%#300#$#Connection#%#keep-alive#$#Referer#%#http://localhost:55000/demoapplication/login.xeb#$#Cookie#%#xuuid=E5573216-8AEC-4187-8ECD-0BC38CF36FF0#$#Content-Type#%#application/x-www-form-urlencoded#$#Content-Length#%#88#E##HO##E##SE##E##A##CT#application/x-www-form-urlencoded#CTE#&l_temp_4=admin&l_temp_6=123&l_temp_8=&servlet_uid_3=servlet_uid_3&l_temp_3=servlet_uid_0#E#
Response Message
The server answers with a response message of the following format:
RESPONSE = {COOKIE_ORDER} CONTENT_TYPE HTML; COOKIE_ORDER = "#C#" cookie_name "=" cookie_value COOKIE_OPT ";Version=1#CE#"; COOKIE_OPT = [";" "Domain=" cookie_domain] [";" "Max-Age=" cookie_max_age] [";" "Path=" cookie_path] [";" "Secure"]; CONTENT_TYPE = "#CT#" content_type; HTML = "#H#" html_code;