Image upload from iPhone strips exif data

Question

I've built a website which allows image uploading and once an image is uploaded , some specific information about the photo is displayed. Uploading pictures from computers works just fine , the problem comes up when I'm trying to upload an image from a smartphone. The upload success but it seems like a major part of the data that is displayed when uploading from computer is now missing.

This code section is the one that actually retrieves and display the data :

$location = $_FILES["pic"]["tmp_name"];
$data = exif_read_data($location);
var_dump($data);

the var_dump($data) actually dumps different data in computers and smartphones.

Apparently it works just fine with Android smartphones, the problem only comes up when I try to upload images from iPhone.

For example, var_dump from computer upload :

array(49) { 
    ["FileName"]=> string(10) "php2D4.tmp" 
    ["FileDateTime"]=> int(1367318152) 
    ["FileSize"]=> int(30357) 
    ["FileType"]=> int(2) 
    ["MimeType"]=> string(10) "image/jpeg" 
    ["SectionsFound"]=> string(24) "ANY_TAG, IFD0, EXIF, GPS" 
    ["COMPUTED"]=> array(6) { 
        ["html"]=> string(24) "width="320" height="240""  
        ["Height"]=> int(240)  
        ["Width"]=> int(320)  
        ["IsColor"]=> int(1)  
        ["ByteOrderMotorola"]=> int(1)  
        ["ApertureFNumber"]=> string(5) "f/2.8"  
    }  
    ["Make"]=> string(5) "Apple"  
    ["Model"]=> string(8) "iPhone 4"  
    ["Orientation"]=> int(3)  
    ["XResolution"]=> string(4) "72/1"  
    ["YResolution"]=> string(4) "72/1"  
    ["ResolutionUnit"]=> int(2)  
    ["Software"]=> string(5) "6.1.3"  
    ["DateTime"]=> string(19) "2013:04:26 23:57:43"  
    ["YCbCrPositioning"]=> int(1)  
    ["Exif_IFD_Pointer"]=> int(204)  
    ["GPS_IFD_Pointer"]=> int(594)  
    ["ExposureTime"]=> string(4) "1/15"  
    ["FNumber"]=> string(4) "14/5"  
    ["ExposureProgram"]=> int(2)  
    ["ISOSpeedRatings"]=> int(1000)  
    ["ExifVersion"]=> string(4) "0221"  
    ["DateTimeOriginal"]=> string(19) "2013:04:26 23:57:43"  
    ["DateTimeDigitized"]=> string(19) "2013:04:26 23:57:43"  
    ["ComponentsConfiguration"]=> string(4) ""  
    ["ShutterSpeedValue"]=> string(9) "4889/1250"  
    ["ApertureValue"]=> string(9) "4281/1441"  
    ["BrightnessValue"]=> string(10) "-3581/1451"  
    ["MeteringMode"]=> int(5)  
    ["Flash"]=> int(24)  
    ["FocalLength"]=> string(5) "77/20"  
    ["SubjectLocation"]=> array(4) {  
        [0]=> int(1295) 
        [1]=> int(967) 
        [2]=> int(699) 
        [3]=> int(696) 
    } 
    ["FlashPixVersion"]=> string(4) "0100" 
    ["ColorSpace"]=> int(1) 
    ["ExifImageWidth"]=> int(2592) 
    ["ExifImageLength"]=> int(1936) 
    ["SensingMethod"]=> int(2) 
    ["ExposureMode"]=> int(0) 
    ["WhiteBalance"]=> int(0) 
    ["FocalLengthIn35mmFilm"]=> int(35) 
    ["SceneCaptureType"]=> int(0) 
    ["GPSLatitudeRef"]=> string(1) "N" 
    ["GPSLatitude"]=> array(3) { 
        [0]=> string(4) "31/1" 
        [1]=> string(8) "5854/100" 
        [2]=> string(3) "0/1" 
    } 
    ["GPSLongitudeRef"]=> string(1) "E" 
    ["GPSLongitude"]=> array(3) { 
        [0]=> string(4) "34/1" 
        [1]=> string(8) "4684/100" 
        [2]=> string(3) "0/1" 
    } 
    ["GPSTimeStamp"]=> array(3) { 
        [0]=> string(4) "20/1" 
        [1]=> string(4) "57/1" 
        [2]=> string(8) "4272/100" 
    } 
    ["GPSImgDirectionRef"]=> string(1) "T" 
    ["GPSImgDirection"]=> string(9) "48089/465" 
}

var_dump from smartphone upload:

array(12) { 
    ["FileName"]=> string(9) "phpSzwfPw" 
    ["FileDateTime"]=> int(1367318054) 
    ["FileSize"]=> int(1778041) 
    ["FileType"]=> int(2) 
    ["MimeType"]=> string(10) "image/jpeg" 
    ["SectionsFound"]=> string(19) "ANY_TAG, IFD0, EXIF" 
    ["COMPUTED"]=> array(5) { 
        ["html"]=> string(26) "width="2592" height="1936"" 
        ["Height"]=> int(1936) 
        ["Width"]=> int(2592) 
        ["IsColor"]=> int(1) 
        ["ByteOrderMotorola"]=> int(1) 
    } 
    ["Orientation"]=> int(3) 
    ["Exif_IFD_Pointer"]=> int(38) 
    ["ColorSpace"]=> int(1) 
    ["ExifImageWidth"]=> int(2592) 
    ["ExifImageLength"]=> int(1936) 
}

Here's the computer var_dump($_FILES) :

    array(1) 
{ ["pic"]=> array(5) 
{ ["name"]=> string(18) leaf2.JPG" 
["type"]=> string(10) "image/jpeg" 
["tmp_name"]=> string(14) "/tmp/phpzeDUs9"
 ["error"]=> int(0)
 ["size"]=> int(46439) } }

Here's the iPhone results var_dump($_FILES) :

    array(1) { ["pic"]=> array(5) 
{ ["name"]=> string(9) "image.jpg" 
["type"]=> string(10) "image/jpeg" 
["tmp_name"]=> string(14) "/tmp/phplPUZky" 
["error"]=> int(0) ["size"]=> int(1455577) } } 

EDIT : Here is the uploading form HTML code:

     <form action="results.php" id="upload-image" method="post" enctype="multipart/form-data">
         <div class="fileupload fileupload-new" data-provides="fileupload">
          <div class="fileupload-preview thumbnail" style="width: 200px; height: 150px;"></div>
          <div>
            <span class="btn btn-file"><span class="fileupload-new">Select image</span><span class="fileupload-exists">Change</span><input type="file" name="pic" id="pic" accept="image/*"/></span>
            <a href="#" class="btn fileupload-exists" data-dismiss="fileupload">Remove</a>
            <button type="submit" class="btn">Upload</button>
            </br>
            <span class="upload-error"></span>
          </div>
     </form>

What might cause it?

Answer 1

The problem

It is correct that the iphone(ipad, etc, i'll just call it iphone from now on) strips exif data. This is also not a bug on the iphone but actually a feature.

One of the main reasons android users don't like the iphone and iphone users don't like the androids, is because the iphone is very limited (in terms of freedom to change, alter, etc). You can not just run downloaded apps, have limited access to settings, etc.

This is because the apple strategy is to create a fail-safe product. "If you can not do strange things, strange things will not happen".It tries to protect the user in every way imaginable. It also protects the user when uploading images. In the exif there may be data that can hurt the users privacy. Things like GPS coordinates, but even a timestamp can hurt a user (imagine you uploading a beach picture with a timestamp from a moment you reported in sick with the boss).

So basically it is a safety meassure to strip all exif data. Myself and a lot of other people do not agree with this strategy, but there is nothing we can do about it unfortunately.

The solution

Update: This does not work. (thanks likeitlikeit for this info)

Luckily you can get around this problem. Javascript comes to the rescue. With javascript you can read the exif data and send it with you photo by adding some extra POST data.

please note: this solution was presented to me by another developer and is not yet tested.

Sources

You are asking for credible sources. Unfortunately they are hard to find as apple is not talking as always and therefore all information i have is hearsay.

perhaps one of the more reliable sources i can present is one of the flickr staffmembers who confirms that the root cause is mobile safari stripping the exif. http://www.flickr.com/help/forum/en-us/72157632100391901/#reply72157632135956813