emailler/ip65/http.s
2018-02-23 16:36:05 +01:00

235 lines
5.1 KiB
ArmAsm

; routines for parsing a HTTP request
; to use - first call http_parse_request, then call http_get_value to get method name, path, and variable values
; NB - this routine uses the same buffer space and zero page locations as many other ip65 routines. so do not call
; other ip65 routines between the http_parse_request & http_get_value else odd things will happen.
.include "zeropage.inc"
.include "../inc/common.inc"
.export http_parse_request
.export http_get_value
.import output_buffer
.import parse_hex_digits
string_ptr = ptr1
table_ptr = ptr2
.bss
var_buf: .res $300 ; work area for storing variables extracted from query string
var_name: .res 1
hex_digit: .res 1
.code
; split a HTTP request into method (e.g. GET or POST), the path, and any querystring variables
; NB only the first letter in a variable name is significant. i.e. if a querystring contains variables 'a','alpha' & 'alabama', only the first one in will be retreivable.
; the method is stored in var $01
; the path is stored in var $02
; for example, parsing "GET /goober?a=foo&alpha=beta" would result in:
; value of A when calling http_get_value value returned by http_get_value
; #$01 "GET"
; #$02 "/goober"
; #'a' "foo"
; #'A' (error)
; inputs:
; AX = pointer to HTTP request
; outputs:
; none - but values can be retrieved through subsequent calls to http_get_value
http_parse_request:
stax string_ptr
ldax #var_buf
stax table_ptr
lda #1 ; start of method
ldy #0
jsr put_byte
lda (string_ptr),y
cmp #'/'
beq @gopher
jsr @check_end_of_string
bcs @gopher
lda (string_ptr),y
@extract_method:
cmp #' '
beq @end_of_method
jsr @check_end_of_string
bcc :+
jmp @done
: jsr put_byte
jsr get_next_byte_in_source
jmp @extract_method
@gopher:
jsr @output_end_of_method
lda #'/'
jmp @got_path_char
@output_end_of_method:
lda #0 ; end of method
jsr put_byte
lda #2 ; start of path
jmp put_byte
@end_of_method:
jsr @output_end_of_method
@extract_path:
jsr get_next_byte_in_source
jsr @check_end_of_string
bcs @done
cmp #'?'
beq @end_of_path
cmp #'&'
beq @end_of_path
@got_path_char:
jsr put_byte
jmp @extract_path
@end_of_path:
lda #0 ; end of path
jsr put_byte
@next_var:
jsr get_next_byte_in_source
jsr @check_end_of_string
bcs @done
jsr put_byte
@skip_to_equals:
jsr get_next_byte_in_source
jsr @check_end_of_string
bcs @done
cmp #'?'
beq @next_var
cmp #'&'
beq @next_var
cmp #'='
beq @got_var
jmp @skip_to_equals
@got_var:
jsr get_next_byte_in_source
jsr @check_end_of_string
bcs @done
cmp #'?'
beq @end_of_var
cmp #'&'
beq @end_of_var
cmp #'%'
beq @get_percent_encoded_byte
cmp #'+'
bne :+
lda #' '
:
@got_byte:
jsr put_byte
jmp @got_var
@end_of_var:
lda #0
jsr put_byte
jmp @next_var
@done:
lda #0
jsr put_byte
jsr put_byte
rts
@check_end_of_string:
cmp #0
beq @end_of_string
cmp #' '
beq @end_of_string
cmp #$0a
beq @end_of_string
cmp #$0d
beq @end_of_string
clc
rts
@end_of_string:
sec
rts
@get_percent_encoded_byte:
jsr get_next_byte_in_source
tax
jsr get_next_byte_in_source
jsr parse_hex_digits
jmp @got_byte
put_byte:
sta (table_ptr),y
inc table_ptr
bne :+
inc table_ptr+1
: rts
; retrieve the value of a variable defined in the previously parsed HTTP request.
; inputs:
; A = variable to retrieve.
; to get the method (GET/POST/HEAD), pass A=$01.
; to get the path (everything between the method and the first '?'), pass A=$02.
; outputs:
; if variable exists in HTTP request, carry flag will be clear and AX points to value (null terminated string)
; if variable did not exist, carry flag will be set.
http_get_value:
sta var_name
ldax #var_buf
stax string_ptr
ldy #0
lda (string_ptr),y
@check_next_var:
beq @end_of_vars
cmp var_name
beq @got_var
; not the var we want, so skip over till next byte
@skip_till_null_byte:
jsr get_next_byte_in_source
bne @skip_till_null_byte
jsr get_next_byte_in_source
bne @check_next_var
@end_of_vars:
sec
rts
@got_var:
jsr get_next_byte_in_source
ldax string_ptr
clc
rts
get_next_byte_in_source:
inc string_ptr
bne :+
inc string_ptr+1
: lda (string_ptr),y
rts
; -- LICENSE FOR http.s --
; The contents of this file are subject to the Mozilla Public License
; Version 1.1 (the "License"); you may not use this file except in
; compliance with the License. You may obtain a copy of the License at
; http://www.mozilla.org/MPL/
;
; Software distributed under the License is distributed on an "AS IS"
; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
; License for the specific language governing rights and limitations
; under the License.
;
; The Original Code is ip65.
;
; The Initial Developer of the Original Code is Jonno Downes,
; jonno@jamtronix.com.
; Portions created by the Initial Developer are Copyright (C) 2009
; Jonno Downes. All Rights Reserved.
; -- LICENSE END --