JSON 64bit decoding bitmap from android to place in mysql BLOB

Question

Sending a image to mysql using android, json and php

I was able to get my bitmap converted to a properly formatted string using

Here is the code in android

JSONObject values = new JSONObject();
            values.put(KEY_CONTRACTUUID, con.UUID);
            ...
            if (con._sig != null) {
                String encodedImage = getStringFromBitmap(con._sig);
                values.put(KEY_CONTRACTSIGIMAGE, encodedImage);


    private static String getStringFromBitmap(Bitmap bitmapPicture) {
        /*
         * This functions converts Bitmap picture to a string which can be
         * JSONified.
         */
        final int COMPRESSION_QUALITY = 100;
        String encodedImage;
        ByteArrayOutputStream byteArrayBitmapStream = new ByteArrayOutputStream();
        bitmapPicture.compress(Bitmap.CompressFormat.PNG, COMPRESSION_QUALITY,
                byteArrayBitmapStream);
        byte[] b = byteArrayBitmapStream.toByteArray();
        encodedImage = Base64.encodeToString(b, Base64.DEFAULT);
        return encodedImage;
    }

now that it is in base64 and a string I need to retrieve it properly to place in my BLOB in mysql

I am not using namevalue pairs or any of that nonsense - simply send it as json and get the json string like so:

$json = json_decode($HTTP_RAW_POST_DATA,true);
echo var_dump(HTTP_RAW_POST_DATA);
...
$varsigimage = $json['sigimage'];

$formatedJSONimage = "{'sigimage': '$varsigimage'}";
var_dump($formatedJSONimage);
$sigImagedecoded = json_decode($formatedJSONimage);
var_dump($sigImagedecoded);

i need to call json_decode on the image to get it out of 64bit to place in the blob correct?

However to do this I need to use the function json_decode, but json_decode assumes I will give it a JSONObject, and since I have many more objects in my $json object, i need to recreate a single JSON object with just the image inside of it, and pass that to the json_decode but it retuns json_error of type SYNTAX

What am I doing wrong, What is the correct approach of converting the base64 string to a blob?

and yes, I am going to have the same question on getting it out of the blob back to a base64 string

azgolfer · Accepted Answer · 2013-02-17 21:37:50Z

1

json_decode parses a JSON string and returns an associative array, mimicking the key/value pairs in the JSON string.

It seems like you are missing another step: you need to decode the base64-encoded image string back to a bitmap. e.g. in your code:

$json = json_decode($HTTP_RAW_POST_DATA,true);
echo var_dump(HTTP_RAW_POST_DATA);
...
$varsigimage = $json['sigimage'];

$image_bitmap = base64_decode($varsigimage); // decode the string back to binary

You should now be able to save $image_bitmap as a BLOB in your database.

answered Feb 17, 2013 at 21:37

azgolfer

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3 Comments

GregM Over a year ago

I actually do have that - part of that tutorial in the original post. I guess i thought there was something special i had to do with it in php. but i just dont touch it and leave it in its string save it to the blob and then send the blob back to me when i need it as is, no other encoding/decoding needed other then the on android side?

azgolfer Over a year ago

If your app is sending the image as base64 encoded string in a JSON string to your server, then your server needs to decode it back to binary, if you want to save it as a BLOB. You can of course save it directly as a base64-encoded string, and decode it on the fly if needed. Bottom line is, if you want to pass JSON between app and server, binary data has to be base64 encoded/decoded between them.

GregM Over a year ago

so that all appears working now - my problem arises that if I store the item as base64 in a BLOB then its format is different then if I insert a image from for instance phpmyadmin, so this is why I would want to decode it from 64 before placing it in the blob correct?

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