Save base64encoded image to server-side database as BLOB

Question

I am taking a photograph from within my Android app using this code:

if (requestCode == CAMERA_REQUEST && resultCode == RESULT_OK){
        photo = (Bitmap) data.getExtras().get("data");
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        photo.compress(Bitmap.CompressFormat.JPEG, 40, baos);
        byte[] photoByte = baos.toByteArray();
        encodedImage = Base64.encodeToString(photoByte,Base64.DEFAULT);
    }

I am sending this String encodedImage to my PHP server through POST and receiving it to $encodedImage. I have a database where I have a field myImage of type MEDIUMBLOB. I tried to save the encodedimage in myImage but it is saved as corrupted image. I tried to save as base64_decode($encodedImage) but somehow that didn't work either.

I want three things to be done:

Save image to server-side database (BLOB)
Show image to a webpage
Send it back to the Android app.

I am facing issues in understanding the conversion of image required in different formats for the above tasks.

For my current project, I don't want to save my image to folder and give link to the database, so that option is closed for me.

My PHP code to save the image:

$baseImage = $_POST['baseImage'];
$blobImage = base64_decode($baseImage);
$query = "INSERT INTO `complaints`(`myImage`,...) VALUES ('$blobImage',...)"
$result = mysqli_query($conn,$query);

did you try `mysqli_real_escape_string()` or a prepared statement for it, either with mysqli_ or PDO? that should work. — Funk Forty Niner, Mar 16 '16 at 13:34
php + mysql is new to me, so i'll have to google that first. I'll definitely search for it. — Srujan Barai, Mar 16 '16 at 13:35
have you tested your encoded image before storing it in database ? — Halayem Anis, Mar 16 '16 at 13:36
since you did tag as mysql figured you'd be using `mysqli_` as your API. If you're using `mysql_` to connect with, then use `mysql_real_escape_string()`. That is unknown to us. You definitely must escape the data going into mysql when saved as a BLOB. — Funk Forty Niner, Mar 16 '16 at 13:36
@HalayemAnis No I didnt. I would have but didnt think of it as I was sending it from phone. — Srujan Barai, Mar 16 '16 at 13:39
what's the size of your image ? if it's greater than 16MB so you have to consider to change from `MEDIUMBLOB` to `LONGBLOB` — Halayem Anis, Mar 16 '16 at 13:43
give us an example of your encoded image, and how you are using it in HTML... — Halayem Anis, Mar 16 '16 at 13:45
@HalayemAnis First, the problem is with saving the image. I have added the php code that I use to add the image. — Srujan Barai, Mar 16 '16 at 13:53

Halayem Anis · Answer 1 · 2016-03-16T14:00:17.587

3

Do not decode your image in PHP, store it as you receive it, Now, in frontend you can print the image as follow

<?php
    $img = '<img src="data:image/jpeg;base64,' . $encodedImgStoredInDB . '">';
    print $img;
?>

edited Mar 16 '16 at 14:00

answered Mar 16 '16 at 13:58

Halayem Anis

7,654
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You mean for the saving purpose I should remove the line `$blobImage = base64_decode($baseImage);` . Rest is ok? – Srujan Barai Mar 16 '16 at 14:00
@SrujanBarai yes :) have you tested it ? – Halayem Anis Mar 16 '16 at 14:16
I did save it that way. Then I went to my database. The myImage field showed me the image. I clicked to download it. But after saving it to computer it was blank image with extension `.bin` – Srujan Barai Mar 16 '16 at 14:19
@SrujanBarai we must keep SO clean, if you have new issue you should create a new thread and i'll be happy to help you :) – Halayem Anis Mar 16 '16 at 14:24
It isn't a new issue. It is just the same issue not solved this way. But I'm working on it. The bigger problem is, I'm new to php and sql, a little bit research and your hint should help. I'm working on it. – Srujan Barai Mar 16 '16 at 14:27

score 1 · Accepted Answer · answered Mar 16 '16 at 14:19

1

Prefix your SQL with the keyword _binary"

$query = "INSERT INTO `complaints`
(`myImage`,...)
VALUES (_binary'".addcslashes($blobImage, "\x00\'\"\r\n")."',...)"

Also, setup a test environment with CURL so that you can throw base64 encoded images at it repeatedly. This is going to be a case where you need lots of debugging.

<?php
$f = fopen('sample.jpg.base64.txt', 'w');
$i = fopen('sample.jpg', 'r');
if (!$i) { die("cannot open sample.jpg\n"); } 
$bytes = '';
while ( ! feof($i)) { 
    $bytes .= fread($i, 4096);
}
fclose($i);
fputs($f, base64_encode( $bytes ) );
fclose($f);

And then use curl to post it repeatedly and debug your PHP

curl -X PUT "http://localhost/myimport.php" -F "baseImage=@./sample.jpg.base64.txt"

Adjust your PHP script to simply write out the data to a file on your hard drive and inspect it there. Write out multiple versions, both encoded and decoded.

Personally, I wouldn't base64 the bytes going from Android to PHP, but I would base64 encode them in mysql.

answered Mar 16 '16 at 14:19

chugadie

2,786
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If you wouldnt base64 the bytes, how would you prefer to transfer then? It will be easy for me to do any changes on the Android side. Your answer is bit heavy for a new commer to php. :\ – Srujan Barai Mar 16 '16 at 14:52
Just send the raw bytes over http. You _can_ base64 encode, the only downside is increased payload size, not a serious issue. http://stackoverflow.com/questions/6360207/android-sending-a-byte-array-via-http-post – chugadie Mar 16 '16 at 15:09
Will it be more appropriate and easy to handle Bytes when received in php? – Srujan Barai Mar 16 '16 at 15:10
nope. You might access them as files from the $_FILES global array as if you had a web page submit an upload. Generally you're just getting some X% larger files transferred before limitations are met where X is the overhead of converting binary to base64. – chugadie Mar 16 '16 at 16:47
Just do both, if the array key $_POST['b64Image'] is set, then process the data as if it were base64 encoded, if $_POST['rawImage'] is set then treat those bytes as a raw JPEG. Then just send whichever you want from the client. – chugadie Mar 16 '16 at 16:49

Save base64encoded image to server-side database as BLOB

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