{"id":68222,"date":"2025-04-28T03:01:00","date_gmt":"2025-04-27T17:01:00","guid":{"rendered":"https:\/\/www.rjmprogramming.com.au\/ITblog\/?p=68222"},"modified":"2025-04-27T15:56:03","modified_gmt":"2025-04-27T05:56:03","slug":"background-image-data-uri-sharing-long-term-recall-tutorial","status":"publish","type":"post","link":"https:\/\/www.rjmprogramming.com.au\/ITblog\/background-image-data-uri-sharing-long-term-recall-tutorial\/","title":{"rendered":"Background Image Data URI Sharing Long Term Recall Tutorial"},"content":{"rendered":"
\"Background<\/a>

Background Image Data URI Sharing Long Term Recall Tutorial<\/p><\/div>\n

The implication of Background Image Data URI Sharing Tutorial<\/a>‘s …<\/p>\n

\n … effectively avoiding the need to ever need to use PHP file_get_contents to retrieve that \/tmp\/ content, which we found was quite a harrowing thing to try?!\n<\/p><\/blockquote>\n

… panning out to be a bug at our end (sorrrrrrrry), opens the door, today, to try out an idea we had regarding an email or SMS recipient’s “lived experience” regarding our Dappled Image Background Image Sharing web application when data URIs were involved with the originator piecing together their creation ahead of sending it to their chosen recipient.<\/p>\n

You may have been reading this thread of postings earlier, and know we started using Document Root<\/a> soft links<\/a>, as per …<\/p>\n

\n … meaning that our PHP helping legend_via_map.php<\/a> changing in this way<\/a> now starts creating Document Root soft links<\/a> (as can happen on Linux and Unix and macOS) pointing back to the \/tmp\/ folder content, no longer a base64 data URI (as was the case with the Media YouTube Interfacer Interspersing Image Text Tutorial<\/a> project style of legend_via_map.php interfacing usage) but actual image file contents<\/font> …\n<\/p><\/blockquote>\n

… to get around errors that could happen as the originator shaped to email or SMS a creation involving image data URI(s). The thing is, though, that our design only stores the \/tmp\/ (web server) content underpinning of the Document Root soft link for a couple of days<\/font> in legend_via_map.php<\/a> changing in this way<\/a> …<\/p>\n

<?php
\n
\n if (isset($_GET['getthisback']) || isset($_GET['andcleanup'])) {
\n if (isset($_GET['getthisback'])) {
\n $fnm=str_replace('+',' ',urldecode($_GET['getthisback']));
\n if (strpos($fnm, 'rjmprogramming.com.au\/bigmedia_') !== false) {
\n \/\/file_put_contents('xv.xv', '\/tmp\/' . explode('.txt', basename($fnm))[0] . '.txt');
\n if (!file_exists('\/tmp\/' . explode('.txt', basename($fnm))[0] . '.txt')) {
\n \/\/file_put_contents('xv0.xv0', '\/tmp\/' . explode('.txt', basename($fnm))[0] . '.txt');
\n echo \"<html><body>Not Found is \" . $fnm . \"<\/body><\/html>\";
\n } else {
\n \/\/file_put_contents('xv1.xv1', '\/tmp\/' . explode('.txt', basename($fnm))[0] . '.txt vs ' . 'http:\/\/' . explode('\/\/', $fnm)[1]);
\n $myfile = fopen('\/tmp\/' . explode('.txt', basename($fnm))[0] . '.txt', \"r\") or die(\"Unable to open file!\");
\n $img_file=fread($myfile,filesize('\/tmp\/' . explode('.txt', basename($fnm))[0] . '.txt'));
\n fclose($myfile);
\n \/\/file_put_contents('xv2.xv2', strlen($img_file) . ' \/tmp\/' . explode('.txt', basename($fnm))[0] . '.txt vs ' . 'http:\/\/' . explode('\/\/', $fnm)[1]);
\n echo \"<html><body><p id=pid>data:image\/\" . explode('.', $fnm)[-1 + sizeof(explode('.', $fnm))] . ';base64,' . base64_encode($img_file) . \"<\/p><\/body><\/html>\";
\n }
\n } else {
\n if (!file_exists($fnm)) {
\n echo \"<html><body>Not found is \" . $fnm . \"<\/body><\/html>\";
\n } else {
\n $myfile = fopen($fnm, \"r\") or die(\"Unable to open file!\");
\n $img_file=fread($myfile,filesize($fnm));
\n fclose($myfile);
\n echo \"<html><body><p id=pid>\" . $img_file . \"<\/p><\/body><\/html>\";
\n }
\n }
\n }
\n if (isset($_GET['andcleanup'])) {
\n foreach (glob('\/tmp\/bigmedia_*.txt') as $tfl) {
\n $filemtime = filemtime($tfl);
\n if (time() - $filemtime >= 172800) {
\n unlink($tfl);
\n }
\n }
\n }<\/font>
\n exit;
\n }
\n<\/code>
\n?> <\/p>\n

… a period of time we consider generous for a recipient to attend to the communication’s link clicking, as interested. But what if that email or SMS link’s content has data URI content which a user may want to recall some days later? Well, we now add a new dropdown option …<\/p>\n


\nCache Data URIs (then Bookmark for later viewing)
\n<\/code><\/p>\n

… which instigates this Javascript when selecting …<\/p>\n


\n alert('We are redirecting you to new webpage that is good to Bookmark (after a few seconds) for future reference, else image data URIs will be forgotten after a couple of days.');
\n location.href=document.URL.replace('cacheit=', 'cacheit=Y');
\n<\/code><\/p>\n

… and then accessing that debugged<\/font> iframe (hosting the call to our helper PHP talked about above) onload event Javascript code …<\/p>\n


\n function checkthis(iois) {
\n if (iois.src.indexOf('About_Us.htm') == -1) {
\n var aconto = (iois.contentWindow || iois.contentDocument);
\n if (aconto != null) {
\n if (aconto.document) { aconto = aconto.document; }
\n
\n if (aconto.body.innerHTML.toLowerCase().indexOf('not found is') != -1) {
\n aconto=aconto;
\n } else if (aconto.body.innerHTML.indexOf('<\/p>') != -1) {
\n dumappings.push(aconto.body.innerHTML.split('<\/p>')[0].split('>')[eval(-1 + aconto.body.innerHTML.split('<\/p>')[0].split('>').length)]);
\n if (numds == 2) {
\n duin=duin.replace(encodeURIComponent(encodeURIComponent(dutmpfiles[eval(-1 + dutmpfiles.length)])), encodeURIComponent(encodeURIComponent(dumappings[eval(-1 + dumappings.length)])));
\n } else {
\n while (duin.indexOf(encodeURIComponent(dutmpfiles[eval(-1 + dutmpfiles.length)])) != -1) {
\n duin=duin.replace(encodeURIComponent(dutmpfiles[eval(-1 + dutmpfiles.length)]), encodeURIComponent(dumappings[eval(-1 + dumappings.length)]));
\n }
\n while (duin.indexOf((dutmpfiles[eval(-1 + dutmpfiles.length)])) != -1) {
\n duin=duin.replace((dutmpfiles[eval(-1 + dutmpfiles.length)]), (dumappings[eval(-1 + dumappings.length)]));
\n }
\n }<\/font>
\n }
\n
\n }
\n }
\n }
\n<\/code><\/p>\n

… we are back with “originator data URI(s)” finding their way back to “recipient webpage data URI referencing background image” webpage data.<\/p>\n

Then, should a recipient want to have the best chance of storing this scenario days out into the future we think it can work if …<\/p>\n