Question

I have an ajax application. It basically uploads images to a folder then PHP grabs them and puts them into an array. From there it is json_encodeded and sent back through echo. alert(responseText) gives me the json version. After I set a variable to json.parse(), with console.log() it comes out fine as an array. The array looks basically like this:

1 IMAGE1.jpg
2 IMAGE2.jpg
3 IMAGE3.jpg
4 IMAGE4.jpg
5 IMAGE5.jpg

etc.

I understand it is now in a javascript/json object. Unfortunately I can’t find any information about manipulating this object to grab all the image names and the last array type which is a true success or failure of the upload. Can anyone point me to some documentation or a way to manipulate this and extrapolate the information into an array. In the end i’m trying to dynamically show these images but I am assuming through the upload they do not all have the same name.

So my hope is to grab all .jpg/.png./gif etc. and grab those filenames and then using innerHTML create a bunch of <img> tags with the correct filename using a loop. As well, handling the last piece in the array which is just text saying if the upload was fully successful or not.

Should I not be using JSON? My code is below.

PHP

$dirhandler = opendir(UPLOAD_DIR);
//create handler to directory

//read all the files from directory
$nofiles=0;
while ($file = readdir($dirhandler)) {
    //if $file isn't this directory or its parent
    //echo "FILE SYSTEM: " . $file . "<br/>";
    //add to the $files array
    if ($file != '.' && $file != '..') {
        $nofiles++;
        $files[$nofiles]=$file;
    } //end of if loop
} //end of while loop
//json_encode($files);
if (!$success) { 
    $nofiles++;
    $files[$nofiles] = "Unable to upload file";
    exit;
} else {
    $nofiles++;
    $files[$nofiles] = "File Upload Successfully";
}
echo json_encode($files);

JAVASCRIPT

   if (xhr.readyState === 4 && xhr.status === 200) {
            progressBar.value="100";
            progressText = "Upload Complete!";
            progressStatus.innerHTML = progressText;
            var imageNames = JSON.parse(xhr.responseText);
            alert(imageNames);
        } else if (xhr.readyState === 0 || xhr.readyState === 1) {
            progressBar.value = "25";
            progressText = "Starting Upload..";
            progressStatus.innerHTML = progressText;
        } else if (xhr.readyState === 2) {
            progressBar.value = "50";
            progressText = "Almost Done...";
            progressStatus.innerHTML = progressText;
        } else if (xhr.readyState === 3) {
            progressBar.value = "75";
            progressText = "So Close!";
            progressStatus.innerHTML = progressText;
        } else if (xhr.status === 404 || xhr.status === 500) {
            alert("Your Upload Request failed.");
        }

Answer 1

imageNames is a nothing-special object–use it like you would use any normal javascript object. E.g.: imageNames[2] will give you the second image name.

However, you life will be much easier if you produce an array that json_encode() will understand as an actual JS array. In your PHP, include an entry for each image instead of using explicit indexes:

$files = array();
$entries = scandir(UPLOAD_DIR);
foreach ($entries as $entry) {
    if (is_file(UPLOAD_DIR.'/'.$entry)) {
        $files[] = $entry;
    }
}
if (!$files) {
    // signal an error with an actual HTTP error code!
    header('Content-Type: application/json', false, 500);
    echo json_encode(array('error'=>'upload failed'));
} else {
    header('Content-Type: application/json');
    echo json_encode($files);
}

However, I suspect that you should be gathering your file names when you process them. Use an upload form with input elements like <input type="file" name="images[]">, then upload to a script with this:

function process_uploaded_files($files, $destdir, $nametmpl) {
    $moved = array();
    foreach ($files['error'] as $key => $error) {
        $newname = FALSE;
        if ($error===UPLOAD_ERR_OK) {
            $source = $files['tmp_name'][$key];
            $destname = sprintf($nametmpl, $key);
            $dest = "{$destdir}/{$destname}";
            if (move_uploaded_file($source, $dest)) {
                // success!
                $newname = $destname;
            }
        }
        $moved[$key] = $newname;
    }
    return $moved;
}

function filename_to_url($filename) {
    // or whatever
    return ($filename) ? '/images/'.$filename : $filename;
}    

$uploaded_files = process_uploaded_files($_FILES['images'], UPLOAD_DIR, 'Image%03d');

// you should always return URLs of resources (not bare filenames) to be RESTful
$new_urls = array_map('filename_to_url', $uploaded_files);
header('Content-Type: application/json');
echo json_encode($new_urls);