httpc.asm

Application sources:A084.ZIP

;
;    HTTPC.ASM
;
;    Compile with FASM for Menuet ( v1.40 for DOS )
;
;    This program implements a very simple web browser
;
;    Version 0.4    2nd December 2003 Mike Hibbett
;    Enabled lowercase/uppcase characters in URL
;    Version 0.3    30th November 2003 Mike Hibbett
;    Fixed bug with tcp socket opne - uses unique port
;    Version 0.2    27th November 2003 Mike Hibbett
;    Added user entry of url, and implements url -> IP address
;    resolution through DNS
;
;    Version 0.1  Ville Mikael Turjanmaa 
;    Original version
   
   
; Enabling debugging puts stuff to the debug board
DEBUGGING_ENABLED           equ     1
DEBUGGING_DISABLED          equ     0
DEBUGGING_STATE             equ     DEBUGGING_DISABLED
   
use32
   
                org     0x0
   
                db      'MENUET00'              ; 8 byte id
                dd      38                      ; required os
                dd      START                   ; program start
                dd      I_END                   ; program image size
                dd      0x100000                ; required amount of memory
                dd      0x00000000              ; reserved=no extended header
                         
   
URLMAXLEN       equ     50  ; maximum length of url string   
   
; Memory usage   
; webpage source file at 0x10000
; decoded text page at   0x20000
; text attribute         0x30000  (1 = normal, 2 = bold, 128+ = link)
   
START:                              ; start of execution
    mov     eax,40                          ; Report events
    mov     ebx,10000111b                   ; Stack 8 + defaults
    int     0x40

    call    draw_window
   
still:
    mov     eax,23                 ; wait here for event
    mov     ebx,1
    int     0x40
   
    cmp     eax,1                  ; redraw request ?
    je      red
    cmp     eax,2                  ; key in buffer ?
    je      key
    cmp     eax,3                  ; button in buffer ?
    je      button
   
    ; Get the web page data from the remote server
    call    read_incoming_data
   
    mov     eax,[status]
    mov     [prev_status],eax
   
    mov     eax,53
    mov     ebx,6
    mov     ecx,[socket]
    int     0x40
    
    mov     [status],eax
   
    cmp     [prev_status],4
    jge     no_send
    cmp     [status],4
    jne     no_send
   
    mov     [onoff],1
   
    call    send_request
   
no_send:
    call    print_status
   
    cmp     [prev_status],4
    jne     no_close
    cmp     [status],4   ; connection closed by server
    jbe     no_close     ; respond to connection close command
                         ; draw page
   
    call    read_incoming_data
   
    mov     eax,53
    mov     ebx,8
    mov     ecx,[socket]
    int     0x40
   
    call    draw_page
   
    mov     [onoff],0
   
no_close:
    jmp     still
   
red:                    ; redraw
    call    draw_window
    jmp     still
   
key:                    ; key
    mov     eax,2       ; just read it and ignore
    int     0x40
    shr     eax,8
    cmp     eax,184
    jne     no_down
    cmp     [display_from],25
    jb      no_down
    sub     [display_from],25
    call    display_page
    
no_down:
    cmp     eax,183
    jne     no_up
    add     [display_from],25
    call    display_page
    
no_up:
    jmp     still
   
button:                 ; button
    mov     eax,17      ; get id
    int     0x40
    cmp     ah,1                   ; button id=1 ?
    jne     noclose
    mov     eax,-1                 ; close this program
    int     0x40
    
noclose:
    cmp     ah,31
    jne     noup
    sub     [display_from],20
    call    display_page
    jmp     still
    
noup:
    cmp     ah,32
    jne     nodown
    add     [display_from],20
    call    display_page
    jmp     still

nodown:
    cmp     ah, 10              ; Enter url
    jne     nourl
    
    mov     [addr],dword document_user
    mov     [ya],dword 38
    mov     [len],dword URLMAXLEN
    
    mov     ecx,[len]
    mov     edi,[addr]
    mov     al,' '
    rep     stosb
   
    call    print_text
   
    mov     edi,[addr]
   
f11:
    mov     eax,10
    int     0x40
    cmp     eax,2 ; key?
    jz      fbu
    jmp     still
    
fbu:
    mov     eax,2
    int     0x40  ; get key
    shr     eax,8
    cmp     eax,8
    jnz     nobs
    cmp     edi,[addr]
    jz      f11
    sub     edi,1
    mov     [edi],byte ' '
    call    print_text
    jmp     f11

nobs:
    cmp     eax, dword 10
    je      retkey
    cmp     eax, dword 13
    je      retkey

    cmp     eax,dword 31
    jbe     f11
    
; Removed in v0.4
;    cmp     eax,dword 95
;    jb      keyok
;    sub     eax,32
  
keyok:
    mov     [edi],al
   
    call    print_text
   
    add     edi,1
    mov     esi,[addr]
    add     esi,URLMAXLEN
    cmp     esi,edi
    jnz     f11
   
    jmp  still
    
retkey:
    mov     ah, 22   ; start load  
        
nourl:
    call    socket_commands     ; opens or closes the connection
    jmp     still
      

;****************************************************************************
;    Function   
;       send_request
;
;   Description
;       Transmits the GET request to the server.
;       This is done as GET then URL then HTTP/1.0',13,10,13,10 in 3 packets
;
;****************************************************************************
send_request:
    pusha
    mov     eax,53     ; 'GET '
    mov     ebx,7
    mov     ecx,[socket]
    mov     edx,4
    mov     esi,string0
    int     0x40
    
    mov     edx,0
    
next_edx:
    ; Determine the length of the url to send in the GET request
    inc     edx
    cmp     [edx+document],byte ' '
    jne     next_edx
   
    mov     eax,53     ; document_user
    mov     ebx,7
    mov     ecx,[socket]
    mov     esi,document
    int     0x40
   
    mov     eax,53     ; ' HTTP/1.0 .. '
    mov     ebx,7
    mov     ecx,[socket]
    mov     edx,stringh_end-stringh
    mov     esi,stringh
    int     0x40
   
    popa
    ret
  

;****************************************************************************
;    Function   
;       print_status
;
;   Description
;       displays the socket/data received status information
;
;****************************************************************************
print_status:   
    pusha
   
    mov     eax,26
    mov     ebx,9
    int     0x40
   
    cmp     eax,[nextupdate]
    jb      status_return
   
    add     eax,25
   
    mov     [nextupdate],eax
   
    mov     eax,13
    mov     ebx,5*65536+100
    mov     ecx,[winys]
    shl     ecx,16
    add     ecx,-18*65536+10
    mov     edx,0xffffff
    int     0x40
   
    mov     eax,47
    mov     ebx,3*65536
    mov     ecx,[status]
    mov     edx,12*65536-18
    add     edx,[winys]
    mov     esi,0x000000
    int     0x40
   
    mov     eax,47
    mov     ebx,6*65536
    mov     ecx,[pos]
    mov     edx,40*65536-18
    add     edx,[winys]
    mov     esi,0x000000
    int     0x40
   
status_return:   
    popa   
    ret
   
   
;****************************************************************************
;    Function   
;       read_incoming_data
;
;   Description
;       receive the web page from the server, storing it without processing
;
;****************************************************************************
read_incoming_data:
    cmp     [onoff],1
    je      rid
    ret
    
rid:
    mov     ecx,-1
   
newbyteread:
    mov     eax, 53
    mov     ebx, 2
    mov     ecx, [socket]
    int     0x40
   
    cmp     eax,0
    je      no_more_data
   
read_more:
    mov     eax, 53
    mov     ebx, 3
    mov     ecx, [socket]
    int     0x40
   
yesm:
    inc     [pos]
    mov     ecx,[pos]
    mov     [0x10000+ecx],bl
   
    call    print_status
   
    cmp     eax,0
    jne     read_more
   
    mov     eax,5
    mov     ebx,50
    int     0x40
   
    jmp     newbyteread
   
no_more_data:   
    ret
     
   
;****************************************************************************
;    Function   
;       draw_page
;
;   Description
;       parses the web page data, storing displayable data at 0x20000
;       and attributes at 0x30000. It then calls display_page to render 
;       the data
;
;****************************************************************************
draw_page:
    pusha
    mov     esi,0
    mov     [command_on_off],0
   
newlettercheck:
    movzx   eax,byte [esi+0x10000]
    cmp     al,'<'
    jne     no_c_on
    mov     [command_on_off],1
    
no_c_on:
    cmp     al,'>'
    jne     no_c_off
    mov     [command_on_off],0
    
no_c_off:
    cmp     [command_on_off],0
    je      no_lower_case
   
    cmp     eax,96
    jg      no_lower_case
    cmp     eax,65
    jb      no_lower_case
    add     eax,32
    
no_lower_case:
    mov     [esi+0x10000],al
    inc     esi
    cmp     esi,[pos]
    jbe     newlettercheck
    mov     edi,0x30000
    mov     ecx,0x10000
    mov     al,0
    cld
    rep     stosb
    mov     [text_type],1
    mov     [command_on_off],0
   
    mov     esi,0
    mov     ecx,[pos]
   
    ; search for double lf
   
find_dlf:
    cmp     [0x10000+esi-4],dword 0x0d0a0d0a
    je      found_dlf
    cmp     [0x10000+esi-4],dword 0x0a0d0a0d
    je      found_dlf
    cmp     [0x10000+esi-2],word 0x0d0d
    je      found_dlf
    cmp     [0x10000+esi-2],word 0x0a0a
    je      found_dlf
   
    cmp     esi,5500
    je      found_dlf
   
    inc     esi
   
    jmp     find_dlf
   
found_dlf:
newbyte:
    mov     al,[esi+0x10000]
    cmp     al,'<'
    jne     no_command_on
    mov     [command_on_off],1
    
no_command_on:
    cmp     al,'>'
    jne     no_command_off
    mov     [command_on_off],0
    jmp     byte_done
    
no_command_off:
    mov     eax,[esi+0x10000]    ; <!--
    cmp     eax,'<!--'
    jne     no_com2_start
    mov     [com2],1
    
no_com2_start:
    mov     ax,[esi+0x10000]    ; -->
    cmp     ax,'->'
    jne     no_com2_end
    mov     [com2],0
    inc     esi
    jmp     byte_done
    
no_com2_end:
    mov     eax,[esi+0x10000]    ; <script
    cmp     eax,'<scr'
    jne     no_script_start
    mov     [script],1

no_script_start:
    mov     eax,[esi+0x10000]    ; /script>
    cmp     eax,'</sc'
    jne     no_script_end
    mov     [script],0
    inc     esi
    jmp     byte_done
    
no_script_end:
    cmp     [command_on_off],0
    jne     no_print
   
    cmp     [com2],0
    jne     no_print
   
    cmp     [script],0
    jne     no_print
  
    mov     al,[esi+0x10000] ; &
    cmp     al,'&'
    jne     no_nbsp
    
newsps:
    inc     esi
    mov     al,[esi+0x10000] ; 
    cmp     al,';'
    jne     newsps
    jmp     byte_done