Re: Extra Data in POST response

On Feb 13, 2023, at 7:35 AM, John Iliffe <john.iliffe@iliffe.ca> wrote: > > On Mon, 2023-02-13 at 04:13 +0000, Ashley Sheridan wrote: >> On 13/02/2023 03:35, John Iliffe wrote: >>> On Sun, 2023-02-12 at 22:41 +0000, Ashley Sheridan wrote: >>>> On 12/02/2023 22:29, John Iliffe wrote: >>>>> On Sun, 2023-02-12 at 21:15 +0000, Ashley Sheridan wrote: >>>>>> On 12/02/2023 19:49, John Iliffe wrote: >>>>>>> I seem to be getting extraneous data in the response sent to the >>>>>>> browser by PHP. >>>>>>> >>>>>>> The server query is an AJAX request in json format which is received >>>>>>> and >>>>>>> processed correctly and the result is sent using the "echo" >>>>>>> function. I have >>>>>>> checked and the area where the response is constructed is empty when >>>>>>> processing >>>>>>> starts. >>>>>>> >>>>>>> The data received by the browser has BOTH the request json data >>>>>>> followed by the >>>>>>> correct response in the received string (result not HTML, just a string >>>>>>> that >>>>>>> will eventually be converted to json but so far will only be caught in >>>>>>> the >>>>>>> browser for display). >>>>>>> >>>>>>> I'm using XMLHttpObject in the browser and I haven't been >>>>>>> able to find a way to >>>>>>> separate the request from the response. Before I construct an elegant >>>>>>> workaround does POST normally return the request? If not, what am I >>>>>>> doing >>>>>>> wrong? So far I have always used GET so I know it doesn't return >>>>>>> the request. >>>>>>> >>>>>>> For completeness, here is what the server says it is sending to the >>>>>>> browser >>>>>>> (using echo) (The json may be wrong; I'm still just trying to >>>>>>> receive it). >>>>>>> >>>>>>> ------ >>>>>>> sent to browser: >>>>>>> >>>>>>> "jres":[{"item_id":"5","i_type":"OL","i_name":"Student >>>>>>> Success >>>>>>> >>>>>>> Pages","i_stock":"99924","i_price":"14.00","i_books_box":"0"},{"item_id":"13","i >>>>>>> _type":"CD","i_name":"Basic Instructors >>>>>>> Guide 9th >>>>>>> >>>>>>> Ed.","i_stock":"9983","i_price":"19.95","i_books_box":"0"},{"item_id":"20","i_ty >>>>>>> pe":"SG","i_name":"Canadian Amateur Radio >>>>>>> Basic Qualification Study >>>>>>> >>>>>>> Guide","i_stock":"274","i_price":"44.95","i_books_box":"20"},{"item_id":"21","i_ >>>>>>> type":"SG","i_name":"Canadian Amateur >>>>>>> Radio Advanced Qualification Study >>>>>>> >>>>>>> Guide","i_stock":"1586","i_price":"49.95","i_books_box":"16"}] >>>>>>> ----- >>>>>>> >>>>>>> here is the original request from the browser, as decoded by server >>>>>>> ------ >>>>>>> request method: POST >>>>>>> requests: array ( >>>>>>> 'req' => >>>>>>> '{"func":"act","item":"438"}', >>>>>>> ) >>>>>>> >>>>>>> json last error message: No error >>>>>>> decoded_args: >>>>>>> func=act >>>>>>> item=438 >>>>>>> >>>>>>> ------- >>>>>>> >>>>>>> and here is what the browser says it received back: >>>>>>> >>>>>>> ----- >>>>>>> received:-->array(2) { >>>>>>> ["func"]=> >>>>>>> string(3) "act" >>>>>>> ["item"]=> >>>>>>> string(3) "438" >>>>>>> } >>>>>>> >>>>>>> >>>>>>> "jres":[{"item_id":"5","i_type":"OL","i_name":"Student >>>>>>> Success >>>>>>> >>>>>>> Pages","i_stock":"99924","i_price":"14.00","i_books_box":"0"},{"item_id":"13","i >>>>>>> _type":"CD","i_name":"Basic Instructors >>>>>>> Guide 9th >>>>>>> >>>>>>> Ed.","i_stock":"9983","i_price":"19.95","i_books_box":"0"},{"item_id":"20","i_ty >>>>>>> pe":"SG","i_name":"Canadian Amateur Radio >>>>>>> Basic Qualification Study >>>>>>> >>>>>>> Guide","i_stock":"274","i_price":"44.95","i_books_box":"20"},{"item_id":"21","i_ >>>>>>> type":"SG","i_name":"Canadian Amateur >>>>>>> Radio Advanced Qualification Study >>>>>>> >>>>>>> Guide","i_stock":"1586","i_price":"49.95","i_books_box":"16"}]<-- >>>>>>> ----- >>>>>>> >>>>>>> Thanks in advance for any suggestions you can give. >>>>>>> >>>>>>> John >>>>>>> ====== >>>>>> Hi John, >>>>>> >>>>>> What does your PHP code look like? Something in it must be outputting >>>>>> the request, as that's not something that would just occur all by >>>>>> itself. >>>>>> >>>>>> Regards, >>>>>> Ash >>>>> Thanks for the quick response Ash. That's what I have been asking myself >>>>> and I >>>>> wondered if returning the query is a requirement of the POST protocol. Without >>>>> sending the entire script, I can say that there are only two "echo" >>>>> statements >>>>> in it (by doing a grep for echo) and they are mutually exclusive: >>>>> >>>>> ----- >>>>> [John@prod04 test]$ grep -n echo ./XXXXXXb.php >>>>> 140: echo $json_resp; >>>>> 145: echo "<br />XXXXXb: Either func or item was not set<br >>>>> />err is true, >>>>> errno=" . $errno . "<br />"; >>>>> ----- >>>>> <?php >>>>> ob_start(); >>>>> /* XXXXXXb responds to AJAX inventory report requests >>>>> * from updated XXXXXXXX. >>>>> * >>>>> * Written J Iliffe 2/2023 >>>>> * copyright John Iliffe, 2023, all rights reserved. >>>>> */ >>>>> //header('Content-Type: application/json; charset=utf-8'); >>>>> header('Content-Type: text/plain; charset=utf-8'); >>>>> $func = ""; >>>>> $item = 0; >>>>> $err = false; >>>>> $errno = 0; >>>>> >>>>> $fx = fopen("/tmp/XXXXXb.txt","w"); >>>>> >>>>> fwrite($fx,("\nrequest method: " . >>>>> $_SERVER['REQUEST_METHOD'])); >>>>> fwrite($fx,("\nrequests: " . var_export($_REQUEST,true))); >>>>> >>>>> /* get the json request block as associative array */ >>>>> if (isset($_POST['req'])) >>>>> { >>>>> $decoded_args = >>>>> json_decode($_POST['req'],true,5,JSON_INVALID_UTF8_IGNORE); >>>>> >>>>> if ((isset($decoded_args['func'])) && >>>>> (isset($decoded_args['item']))) >>>>> { >>>>> $func = $decoded_args['func']; >>>>> $item = $decoded_args['item']; >>>>> fwrite($fx,("\nfunc and item isset as " . $func . >>>>> " and " . $item . >>>>> "\n")); >>>>> } >>>>> else >>>>> { >>>>> $err = true; >>>>> $errno = 2; >>>>> } >>>>> >>>>> fwrite($fx,("\njson last error message: " . >>>>> json_last_error_msg() . >>>>> "\n")); >>>>> fwrite($fx,("decoded_args:" . var_dump($decoded_args) . >>>>> "\n")); >>>>> fwrite($fx,("func=" . $decoded_args['func'] . >>>>> "\n")); >>>>> fwrite($fx,("item=" . $decoded_args['item'] . >>>>> "\n")); >>>>> } >>>>> else >>>>> { >>>>> $err = true; >>>>> $errno = 1; >>>>> } >>>>> >>>>> /* if we are good to go here, open database, create query */ >>>>> $json_resp = '"jres":['; //json opening >>>>> >>>>> ----I deleted the database activity from here--- >>>>> >>>>> if (! $err) >>>>> { >>>>> if (! $res) >>>>> { >>>>> $err=true; >>>>> $errno = 4; >>>>> } >>>>> else >>>>> { >>>>> for ($i=0;$i<$rows;$i++) >>>>> { >>>>> $r_arr = pg_fetch_array($res,null,PGSQL_ASSOC); >>>>> >>>>> $json_rec=json_encode($r_arr,0,16); >>>>> >>>>> if ($json_rec === false) >>>>> { >>>>> fwrite ($fx,("\nrecord at " . $i . " bad, >>>>> " . >>>>> json_last_error_msg() . "\n")); >>>>> } >>>>> >>>>> >>>>> if (($i < $rows) && ($i != 0)) // no opening or >>>>> trailing ',' >>>>> { >>>>> $json_resp .= ','; >>>>> } >>>>> >>>>> $json_resp .= $json_rec; >>>>> } >>>>> >>>>> $json_resp .= ']'; >>>>> >>>>> fwrite($fx,("\njson sent to browser:\n -->" . $json_resp . >>>>> "<---\n\n\n")); >>>>> } >>>>> } >>>>> } >>>>> >>>>> if (! $err) >>>>> { >>>>> echo $json_resp; >>>>> ob_flush(); >>>>> } >>>>> else >>>>> { >>>>> echo "<br />adm9005b: Either func or item was not set<br >>>>> />err is true, >>>>> errno=" . $errno . "<br />"; >>>>> ob_flush(); >>>>> } >>>>> >>>>> exit; >>>>> ?> >>>>> ------ >>>>> >>>>> This is pretty much what I have so far and why it has been driving me nuts for >>>>> several days now...the query is never repeated anywhere in the echoed output. >>>>> What actually comes back to the browser, as you can see above, is is the result >>>>> generated by this; prepended with PHP's analysis of the original POST >>>>> query. >>>>> >>>>> Thanks for taking the time to look. >>>>> >>>>> John >>>>> ====== >>>> It might be some error output, which is being supressed by the >>>> ob_start(), and then output when you do the ob_flush(). Why are you >>>> using those, as it's unusual for what you appear to be doing here. >>>> >>>> Thanks, >>>> Ash >>>> >>> Thanks for the suggestion Ash. I commented out the ob_start and ob_flush >>> statements but the problem persists. >>> >>> I was using buffering because I have to send headers as part of the response, at >>> the very least the content-type header when I convert the response to json. The >>> reason it is a simple string at the moment is that I didn't want my inexperience >>> with json to get involved with getting the communications working properly. >>> >>> Regards, >>> >>> John >>> ====== >> >> Have you tried attaching a debugger, to see at what point the extra >> output is being shown? Is it being added to the response variable >> somewhere, possibly from the code that you removed from your excerpt? >> >> Also, you don't need to use object buffers if you're sending headers. >> Typically, you'd use output buffering if you wanted to prevent something >> from making it to the final output, or if you needed to control the >> output during a streamed response. >> >> Thanks, >> Ash > ======= > Thank you Ash. As it turned out, the note from Janis has the answer, var_dump > outputs rather than returning a value so it was doing a sort of a phantom "echo" > in the background. Sorry to have wasted your time. > > Also, thanks very much for the comments of the output buffering. I read > somewhere that if it was necessary to send headers then I have to buffer the > output to avoid having any html sent before the headers and I, mistakenly, > assumed that I would have to do that here, even though no html is being sent. > Works properly without buffering so I will delete that. That, I suppose, is the > result of learning while doing! (I'm the only one here that works on the > server, and I'm also the sysadmin, operator, and network guy) > > Regards, and thanks, > > John > ====== ———————— Not a waste of time if we all learn something! George Langley