Fopen Serial Port Php - talktorrent93’s blog

With COM ports Windows, fread sees nothing until 8K: Open a COM port as a serial input using fopen. de port. I work in project with PHP to SEND SMS with.

If there is a file that s excessively being rewritten by many different users, you ll note that two almost-simultaneously accesses on that file could interfere with each other. For example if there s a chat history containing only the last 25 chat lines. Now adding a line also means deleting the very first one. So while that whole writing is happening, another user might also add a line, reading the file, which, at this point, is incomplete, because it s just being rewritten. The second user would then rewrite an incomplete file and add its line to it, meaning: you just got yourself some data loss.

If flock was working at all, that might be the key to not let those interferences happen - but flock mostly won t work as expected at least that s my experience on any linux webserver I ve tried, and writing own file-locking-functions comes with a lot of possible issues that would finally result in corrupted files. Even though it s very unlikely, it s not impossible and has happened to me already.

So I came up with another solution for the file-interference-problem:

1. A file that s to be accessed will first be copied to a temp-file directory and its last filemtime is being stored in a PHP-variable. The temp-file gets a random filename, ensuring no other process is able to interfere with this particular temp-file.

2. When the temp-file has been changed/rewritten/whatever, there ll be a check whether the filemtime of the original file has been changed since we copied it into our temp-directory.

2.1. If filemtime is still the same, the temp-file will just be renamed/moved to the original filename, ensuring the original file is never in a temporary state - only the complete previous state or the complete new state.

2.2. But if filemtime has been changed while our PHP-process wanted to change its file, the temp-file will just be deleted and our new PHP-fileclose-function will return a FALSE, enabling whatever called that function to do it again ie. upto 5 times, until it returns TRUE.

These are the functions I ve written for that purpose:

. php

dir_fileopen . ./AN/INTERNAL/DIRECTORY/fileopen randomid

return time. substr md5 microtime, 0, rand 5, 12cfopen filename, mode, overwriteanyway false

global dir_fileopen;

clearstatcache ;

id md5 randomid rand, TRUE ;

tempfilename dir_fileopen. /. id.md5 filename ;

while file_exists tempfilename ;

if file_exists filename

newfile false;

copy filename, tempfilename ;

else

newfile true;

fp fopen tempfilename, mode ;

return fp. array fp, filename, id, filemtime filename, newfile, overwriteanyway : falsecfwrite fp, string return fwrite fp 0, stringcfclose fp, debug off

success fclose fp 0 ;

tempfilename dir_fileopen. /. fp 2. md5 fp 1 ;

if filemtime fp 1 fp 3 or fp 4 true and. file_exists fp 1 or fp 5 true

rename tempfilename, fp 1 ;

unlink tempfilename ;

if debug. off echo While writing, another process accessed fp 1. To ensure file-integrity, your changes were rejected. ;

success false;

return success;

overwriteanyway, one of the parameters for cfopen, means: If cfclose is used and the original file has changed, this script won t care and still overwrite the original file with the new temp file. Anyway there won t be any writing-interference between two PHP processes, assuming there can be no absolute simultaneousness between two or more processes.

Examples. This example creates the serial port object s, connects s to the device using fopen, writes and reads text data, and then disconnects s from the device.

This function has a basic implementation of HTTP Digest Authentication as per RFC 2617 to get a file from a web server which requires digest authentication as opposed to basic authentication - the difference being that, with basic, your password is sent to the server as plain text, whereas with digest, it is hashed with a server-supplied nonce to protect against sniffing and replay attacks.

You just supply the host e.g www.example.com, the name of the file you want e.g protected_page.html, and the necessary username and password, and the function returns the contents of the protected file or the error message that the server sends, if you supplied the wrong credentials.

If the server only supports a QOP of auth-int rather then auth this function won t work, but can be easily modified with reference to the RFC at

. php

function readHTTPDigestAuthenticatedFile host, file, username, password

if . fp fsockopen host,80, errno, errstr, 15

return false;

out GET / file HTTP/1.1 r n ;

out. Host: host r n ;

out. Connection: Close r n r n ;fwrite fp, out ;while . feof fp

line fgets fp, 512 ;

if strpos line, WWW-Authenticate. false

authline trim substr line,18 ;

fclose fp ;

authlinearr explode, , authline ;

autharr array ;

foreach authlinearr as el

elarr explode, el ;

autharr trim elarr 0 substr elarr 1, 1,strlen elarr 1 -2 ;

foreach autharr as k v

echo k v r n ;

nonce autharr nonce ;

opaque autharr opaque ;

drealm autharr Digest realm ;

cnonce sausages ;

a1 username: drealm: password ; a2 GET:/ file ;

ha1 md5 a1 ; ha2 md5 a2 ;

concat ha1. . nonce. :00000001. cnonce. :auth. ha2;

response md5 concat ;

out. Connection: Close r n ;

out. Cookie: cookie MyCookie r n ;

out. Authorization: Digest username username, realm drealm, qop auth, algorithm MD5, uri / file, nonce nonce, nc 00000001, cnonce cnonce, opaque opaque, response response r n r n ;

fwrite fp, out ;

while . feof fp

str. fgets fp, 512 ;

return str;

fopen

Writing and reading on a serial port. That will usually create a new empty file that you can write to even when fopen fails. - PHP 4.3.0. up. down. 0.
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It is simple to control serial via PHP.. php exec mode com4: BAUD 9600 PARITY n DATA 8 STOP 1 to off dtr off rts off ; fp fopen Open USB serial port for.

This MATLAB function writes the binary data A to the device connected to the serial port object, obj.