My webserver is receiving image data from an iOS App via HTTP POST.
The transmitted image-data looks like this:
$postvar1=x&image=<89504e47 0d0a1a0a 0000000d 49484452 00000100 00000064 08060000 006960ee 9e000020 00494441 547801ed 5d099c14 c5b9afea 9ed9fb98 5941c428 a2c62320 0a8a8047 3cf06017 573cc178 c0eea246 8db9f4f9 e22f79fa 7c26e6c5 f78cd1e4 19351ad9 5d0ea360 3c815d62 bc350a51 f008781b 82181570 67f66477
I don't know what to do with this string in PHP. What kind of encoding is it?
Thanks!
Its a PNG file.
The PNG Magic number is 8950.4e47.0d0a.1a0a
ASCI \x89PNG\r\n\x1a\n
It's binary, it's an image file, it can't "Do" anything with it as it is...
And according to my hex editor, it's a PNG...
Since the other answers miss it: It what you get from -[NSData description] (a hexdump between angle brackets, like <01234567 89ABCDEF>). This probably happens due to someone doing something like [NSString stringWithFormat:#"blah&image=%#", data]. The reasons why this is terrible are too numerous to mention.
It's far, far preferable to upload as multipart/form-data or (if you send any other fields you need in a header) just image/png or application/octet-stream. The hexdump overhead is huge.
It's a png here is it
http://i.stack.imgur.com/bUXLb.png
256x100 but it's just transparent
If you want to convert it in php have a look at the pack function
Related
Okay, this is driving me crazy. I have a small file. Here is the dropbox link https://www.dropbox.com/s/74nde57f07jj0zj/transcript.txt?dl=0.
If I try to read the content of the file using python f.read(), I can easily read it. But, if I try to run the same python program using php shell_exec(), the file read fails. This is the error I get.
Traceback (most recent call last):
File "/var/www/python_code.py", line 2, in <module>
transcript = f.read()
File "/opt/anaconda/lib/python3.4/encodings/ascii.py", line 26, in decode
return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2 in position 107: ordinal not in range(128)
I have checked all the permission issues and there is no problem with that.
Can anyone kindly shed some light?
Here is my python code.
f = open('./transcript/transcript.txt', 'r')
transcript = f.read()
print(transcript)
Here is my PHP code.
$output = shell_exec("/opt/anaconda/bin/python /var/www/python_code.py");
Thank you!
EDIT: I think the problem is in the file content. If I replace the content with simple 'I eat rice', then I can read the content from php. But the current content cannot be read. Still don't know why.
The problem appears is that your file contains non-ASCII characters, but you're trying to read it as ASCII text.
Either it is text, but is in some encoding or other that you haven't told us (probably UTF-8, Latin-1, or cp1252, but there are countless other possibilities), or it's not text at all, but rather arbitrary binary data.
When you open a text file without specifying an encoding, Python has to guess. When you're running from inside the terminal or whatever IDE you use, presumably, it's guessing the same encoding that you used in creating the file, and you're getting lucky. But when you're running from PHP, Python doesn't have as much information, so it's just guessing ASCII, which means it fails to read the file because the file has bytes that aren't valid as ASCII.
If you want to understand how Python guesses, see the docs for open, but briefly: it calls locale.getpreferredencoding(), which, at least on non-Windows platforms, reads it from the locale settings in the environment. On a typical linux system that's not new enough to be based on systemd but not too old, the user's shell will be set up for a UTF-8 locale, but services will be set up for C locale. If all of that makes sense to you, you may see a way to work around your problem. If it all sounds like gobbledegook, just ignore it.
If the file is meant to be text, then the right solution is to just pass the encoding to the open call. For example, if the file is UTF-8, do this:
f = open('./transcript/transcript.txt', 'r', encoding='utf-8')
Then Python doesn't have to guess.
If, on the other hand, the file is arbitrary binary data, then don't open it in text mode:
f = open('./transcript/transcript.txt', 'rb')
In this case, of course, you'll get bytes instead of str every time you read from it, and print is just going to print something ugly like b'aq\x9bz' that makes no sense; you'll have to figure out what you actually want to do with the bytes instead of printing them as a bytes.
How to extract metadata from a image like this website? I have used exev2 library but it gives only limited data as compared to this website. Is there some more advanced library?
I have already tried hacoir-metadata Python library.
Also how does Windows extract details of image (the one we see from properties)?
PNG files are made up of blocks, most of which are IDAT blocks which contain compressed pixel data in an average PNG. All PNG's start with a IHDR block and end with an IEND block. Since PNG is a very flexible standard in this way, it can be extended by making up new types of blocks--this is how animated Animated PNG works. All browsers can see the first frame, but browsers which understand the types of blocks used in APNG can see the animation.
There are many places that text data can live in a PNG image, and even more places metadata can live. Here is a very convenient summary. You mentioned the "Description tag", which can only live in text blocks, so that it was I'll be focusing on.
The PNG standard contains three different types of text blocks: tEXt (Latin-1 encoded, uncompressed), zTXt (compressed, also Latin-1), and finally iTXt, which is the most useful of all three as it can contain UTF-8 encoded text and can either be compressed or decompressed.
So, your question becomes, "what is a convenient way to extract the text blocks?"
At first, I thought pypng could do this, but it cannot:
tEXt/zTXt/iTXt
Ignored when reading. Not generated.
Luckily, Pillow has support for this - humorously it was added only one day before you asked your original question!
So, without further ado, let's find an image containing an iTXt chunk: this example ought to do.
>>> from PIL import Image
>>> im = Image.open('/tmp/itxt.png')
>>> im.info
{'interlace': 1, 'gamma': 0.45455, 'dpi': (72, 72), 'Title': 'PNG', 'Author': 'La plume de ma tante'}
According to the source code, tEXt and zTXt are also covered.
For the more general case, looking over the other readers, the JPEG and GIF ones also seem to have good coverage of those formats as well - so I would recommend PIL for this. That's not to say that the maintainers of hacoir-metadata wouldn't appreciate a pull request adding text block support though! :-)
I found this code buried in a Pillow pull request
from PIL import PngImagePlugin
info = PngImagePlugin.PngInfo() # read PNG data
info.add_text("foo", "bar") # write PNG data
img.save(filenew, "png", pnginfo=info)
You can try this pre-alpha solution by Daniel Chesterton. I am not sure is it just what you want or is it a part of the wanted solution, but I believe you can sort it out by playing with it.
https://github.com/dchesterton/image
I have a sever which people can upload files to. The problem is that some of the filenames are mangled (dont have any extension) and so I cannot immediately determine file type. This question is two part: for the files which do have filenames what is the best way to determine whether or not it is an image? (Just a big long if/else if list?) Secondly, for the files which dont have extensions, how can I determine if they are images?
You can use exif_imagetype()
<?php
$type =exif_imagetype($image);
where $type is a value
IMAGETYPE_GIF
IMAGETYPE_JPEG
IMAGETYPE_PNG
IMAGETYPE_SWF
IMAGETYPE_PSD
IMAGETYPE_BMP
IMAGETYPE_TIFF_II (intel byte order)
IMAGETYPE_TIFF_MM (motorola byte order)
IMAGETYPE_JPC
IMAGETYPE_JP2
IMAGETYPE_JPX
IMAGETYPE_JB2
IMAGETYPE_SWC
IMAGETYPE_IFF
IMAGETYPE_WBMP
IMAGETYPE_XBM
IMAGETYPE_ICO
From the manual:
When a correct signature is found, the appropriate constant value will be returned otherwise the return value is FALSE. The return value is the same value that getimagesize() returns in index 2 but exif_imagetype() is much faster.
You can use getimagesize
It does not require the GD image library and it returns same information about image type.
http://it2.php.net/manual/en/function.getimagesize.php
If you have the GD2 extension enabled, you could just use that to load the file as an image, then if it returns invalid you can catch the error and return FALSE, otherwise return TRUE.
You have two options here, one's simple and pre-built with some shortfalls, the other is complex and requires math.
PHP's fileinfo can be used to detect file types based on the file's actual header information. For instance, I just grabbed your gravitar:
But the actual code is this:
‰PNG
IHDR szzô
IDATX…—OL\UÆZÀhëT)¡ c•1T:1‘Š‘.Ú(]4†A“ÒEY˜à.................................
So, even without the file name I could detect it quite obviously. This is what the PHP Fileinfo extension will do. Most PNG and JPG files tend to have this header in them, but this is not so for every single file type.
That being said, fileinfo is dead simple to use, from the manual:
$fi = new finfo(FILEINFO_MIME,'/usr/share/file/magic');
$mime_type = $fi->buffer(file_get_contents($file));
Your other option is more complex and it depends on your own personal ambitions, you could generate a histogram and profile files based on their content.
Something like this looks like a GIF file:
And something like this looks like a TIFF file:
From there you'd need to generate a model over multiple types of files for what the histogram of each type should be, and then use that to guess. This is a good method to use for files that don't really have those "magic headers" that can be read easily. Keep in mind, you'll need to learn some math and how to model an average histogram function and match them against files.
You can try to load the image into PHP's GD library, and see if it works.
$file = file_get_contents('file');
$img = imagecreatefromstring($file);
if($img === FALSE){
// file is NOT an image
}
else{
// file IS an image
}
Look at image magic identify. http://www.imagemagick.org/script/identify.php
The php wrapper is here: http://www.php.net/manual/en/function.imagick-identifyimage.php
Or if you just want to validate that it's an image (and don't care about the meta data): http://www.php.net/manual/en/function.imagick-valid.php
exif_imagetype() might work
make sure you have exif enabled.
Try looking at exif_imagetype
If you need a fast solution, use imagesx() and imagesy(). There is also a fast way to check large image file dimensions, by reading just a small amount of data from the file header. Explained in more detail in the following url:
http://hungred.com/useful-information/php-fastest-image-width-height/
You can use the Fileinfo extension:
http://www.php.net/manual/en/function.finfo-file.php
finfo_file() uses magic bytes and does not have to load the whole image into memory. The result is a string with the corresponding MIME type, e.g.:
text/html
image/gif
application/vnd.ms-excel
The type of the image is typically going to be able to be inferenced from the header information of the file.
For the first question is extension is known you could use the PHP function in_array() Documentation
I'm trying to create a script that pulls an image out of the database and displays it to the user, called by <img src="viewImage/someImageName">
But the problem I'm having is when the image is displayed all of the Nulls (0x00) are replaced by 0x20 and I have no idea why. The data in the database shows it being nulls but somewhere along the way it gets changed to 0x20s.
Does anyone have any idea? is there something I'm missing?
Here is the code I'm using:
$data = $this->Image->read(NULL, $userId);
header("Content-Type: image/jpeg");
echo($data['image']);
die;
I don't think it has anything to do with the code because as you can see there is no place for error. I can dump the binary contents out and it has not yet been tampered.
Something with the stack or cakephp any thoughts?
Update:
I've noticed that a space is making to the beginning of stream, I'm trying to track it down, could this be the problem?
Yeah, something along the way is freaking out (because OMG nulls, what if something thinks they're string terminators) and replacing them with spaces. I suspect CakePHP but am not quite certain enough to say j'accuse. Try:
header('Transfer-Encoding-Type: base64');
and see if that convinces whatever's doing it to leave your data alone.
I had a stray space in a file somewhere, lots of fun to track down :)
I guess this switches the mode of something in the stack and corrupts the files
I am building an open search add-on for Firefox/IE and the image needs to be Base64 Encoded so how can I base 64 encode the favicon I have?
I am only familiar with PHP
As far as I remember there is an xml element for the image data. You can use this website to encode a file (use the upload field). Then just copy and paste the data to the XML element.
You could also use PHP to do this like so:
<?php
$im = file_get_contents('filename.gif');
$imdata = base64_encode($im);
?>
Use Mozilla's guide for help on creating OpenSearch plugins. For example, the icon element is used like this:
<img width="16" height="16">data:image/x-icon;base64,imageData</>
Where imageData is your base64 data.
$encoded_data = base64_encode(file_get_contents('path-to-your-image.jpg'));
My synopsis of rfc2397 is:
Once you've got your base64 encoded image data put it inside the <Image></Image> tags prefixed with "data:{mimetype};base64," this is similar to the prefixing done in the parenthesis of url() definition in CSS or in the quoted value of the src attribute of the img tag in [X]HTML. You can test the data url in firefox by putting the data:image/... line into the URL field and pressing enter, it should show your image.
For actually encoding I think we need to go over all your options, not just PHP,
because there's so many ways to base64 encode something.
Use the base64 command line tool. It's part of the GNU coreutils (v6+) and pretty much default in any Cygwin, Linux, GnuWin32 install, but not the BSDs I tried. Issue: $ base64 imagefile.ico > imagefile.base64.txt
Use a tool that features the option to convert to base64, like Notepad++ which has the feature under plugins->MIME tools->base64 Encode
Email yourself the file and view the raw email contents, copy and paste.
Use a web form.
A note on mime-types:
I would prefer you use one of image/png image/jpeg or image/gif as I can't find the popular image/x-icon. Should that be image/vnd.microsoft.icon?
Also the other formats are much shorter.
compare 265 bytes vs 1150 bytes:
data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAMAAAAoLQ9TAAAAVFBMVEWcZjTcViTMuqT8/vzcYjTkhhTkljT87tz03sRkZmS8mnT03tT89vTsvoTk1sz86uTkekzkjmzkwpT01rTsmnzsplTUwqz89uy0jmzsrmTknkT0zqT3X4fRAAAAbklEQVR4XnXOVw6FIBBAUafQsZfX9r/PB8JoTPT+QE4o01AtMoS8HkALcH8BGmGIAvaXLw0wCqxKz0Q9w1LBfFSiJBzljVerlbYhlBO4dZHM/F3llybncbIC6N+70Q7OlUm7DdO+gKs9gyRwdgd/LOcGXHzLN5gAAAAASUVORK5CYII=
data:image/x-icon;base64,AAABAAEAEBAAAAEAIABoBAAAFgAAACgAAAAQAAAAIAAAAAEAIAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAD/////ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv///////////2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb///////////9mZmb/ZmZm//////////////////////////////////////////////////////9mZmb/ZmZm////////////ZmZm/2ZmZv//////ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv//////ZmZm/2ZmZv///////////2ZmZv9mZmb//////2ZmZv9mZmb/ZmZm/2ZmZv9mZmb/ZmZm/2ZmZv9mZmb//////2ZmZv9mZmb///////////9mZmb/ZmZm////////////////////////////8fX4/8nW5P+twtb/oLjP//////9mZmb/ZmZm////////////////////////////oLjP/3eZu/9pj7T/M2aZ/zNmmf8zZpn/M2aZ/zNmmf///////////////////////////////////////////zNmmf8zZpn/M2aZ/zNmmf8zZpn/d5m7/6C4z/+WwuH/wN/3//////////////////////////////////////+guM//rcLW/8nW5P/x9fj//////9/v+/+w1/X/QZ7m/1Cm6P//////////////////////////////////////////////////////7/f9/4C+7v8xluT/EYbg/zGW5P/A3/f/0933/9Pd9//////////////////////////////////f7/v/YK7q/xGG4P8RhuD/MZbk/7DX9f//////4uj6/zJh2/8yYdv/8PT8////////////////////////////UKbo/xGG4P8xluT/sNf1////////////4uj6/zJh2/8jVtj/e5ro/////////////////////////////////8Df9/+gz/P/////////////////8PT8/0944P8jVtj/bI7l/////////////////////////////////////////////////////////////////2yO5f8jVtj/T3jg//D0/P///////////////////////////////////////////////////////////3ua6P8jVtj/MmHb/+Lo+v////////////////////////////////////////////////////////////D0/P8yYdv/I1bY/9Pd9///////////////////////AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA==
Check the following example:
// First get your image
$imgPath = 'path-to-your-picture/image.jpg';
$img = base64_encode(file_get_contents($imgPath));
echo '<img width="100" height="100" src="data:image/jpg;base64,'. $img .'" />'
Google led me to this solution (base64_encode). Hope this helps!