pdf to base64 php
Uploading PDF files as base64 strings in PHP and saving it in the hard-disk.
If you’re reading this post, chances are you’re having some issues when trying to upload (PDF) files as base64 strings to later store them “physically” in the hard-disk. No worries, it might be simpler than you think and I got you covered in this article. 😉
I’ve spent a few hours on the other day trying to figure out how to do it right. Neither Google nor Stackoverflow helped me at that time, as I searched for a while without any luck on finding any working solution! So, I hope this can help you.
First, a bit of context.
My team and I am building a Single Page Application (SPA) CRM which has a feature where the employees are required to upload a PDF file, via an ajax call against a RESTful API. As per the requirements, once received, the PDF file should be “physically” stored in the server alongside other documents (not in the database).
The approach taken was to convert the PDF file into a base64 string and submit that alongside the complementary data via POST method. The API, then, would be responsible to get that string and reconstruct the file to be stored in the disk.
Implementing this was fairly simple, however, it took us a while until we manage to properly revert the base64 string into the PDF file to be saved.
Here is how we’ve initially coded it:
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With the above approach, everything was working fine except by the fact that the saved PDF file was getting “corrupted” and one was not been able to open it back.
The problem was that when converting the PDF file to a base64 string, it receives an extra piece of data as a prefix ( data:application/pdf;base64, ) which when converted back to PDF simply corrupts the file.
So, as you may have already figured out, the solution was simply removing the base64 header from the string before converting it back to PDF, as follows:
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As you may see above, to get it working we just had to include the following conditional block to the function we’ve written before:
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And if the base64 prefix is found, all that needs to be done is removing it from the string before writing it back in the hard disk as a PDF file! 🤘
That’s pretty much it.
I hope it can help you to not be struggling with such a simple issue, as I was for a few hours until figure this out! 😉
print BASE64 coded image into a FPDF document
I’ve some as base64 stored images in a database. Is it possible to print those data directly in a PDF document, using FPDF?
Data sctructure of the image
8 Answers 8
While the comments suggested a TCPDF solution, I did want to state that there is a way to do this entirely with FPDF. The thought process is like this:
Always remember to error check. If the image fails to save to the server you obviously do not want to continue execution. Make sure to always strictly check if the functions return false!
Here is my solution. I used a tiny image for a small URI in this example.
I know this is an old topic, but there is an easier way of solving this problem. Just try this simple steps:
Remember to choose the correct image type for Image() method call.
To ensure the images work with FPDF and to avoid errors, here is a modified version of @pedro-soares’ code:
Because FPDF only allows these three file types, it is important to check that it is valid. To use:
To add a bit more to Mari M answer, I just added few lines to work with any types of images. (as for me FPDF complains if the image is jpeg and I try to load tempimg.png)
I am sure there is a better way to do that with regular expression, but to be honest, regexp is not my cup of tea.
Ok, I wasted half day making test with this issue. I have to tell that this solution is for print images from db row, directly, without stored them on temp files.
I´m going to write some points to consider:
Then the only thing that you have to do is:
I just add this to the last code:
base64_encode
(PHP 4, PHP 5, PHP 7, PHP 8)
base64_encode — Кодирует данные в формат MIME base64
Описание
Кодирует string с base64.
Эта кодировка предназначена для корректной передачи бинарных данных по протоколам, не поддерживающим 8-битную передачу, например, для отправки тела письма.
Данные, закодированные base64 занимают на 33% больше места по сравнению с оригинальными данными.
Список параметров
Данные для кодирования.
Возвращаемые значения
Кодированные данные в виде строки.
Примеры
Пример #1 Пример использования base64_encode()
Результат выполнения данного примера:
Смотрите также
User Contributed Notes 35 notes
For anyone interested in the ‘base64url’ variant encoding, you can use this pair of functions:
gutzmer at usa dot net’s ( http://php.net/manual/en/function.base64-encode.php#103849 ) base64url_decode() function doesn’t pad longer strings with ‘=’s. Here is a corrected version:
function base64_encode_url($string) <
return str_replace([‘+’,’/’,’=’], [‘-‘,’_’,»], base64_encode($string));
>
Checked here with random_bytes() and random lengths:
Unfortunately my «function» for encoding base64 on-the-fly from 2007 [which has been removed from the manual in favor of this post] had 2 errors!
The first led to an endless loop because of a missing «$feof»-check, the second caused the rare mentioned errors when encoding failed for some reason in larger files, especially when
setting fgets($fh, 2) for example. But lower values then 1024 are bad overall because they slow down the whole process, so 4096 will be fine for all purposes, I guess.
The error was caused by the use of «empty()».
Here comes the corrected version which I have tested for all kind of files and length (up to 4,5 Gb!) without any error:
$cache = » ;
$eof = false ;
Base64 encoding of large files.
So if you read from the input file in chunks of 8151 (=57*143) bytes you will get (up to) 8151 eight-bit symbols, which encode as exactly 10868 six-bit symbols, which then wrap to exactly 143 MIME-formatted lines. There is no need to retain left-over symbols (either six- or eight-bit) from one chunk to the next. Just read a chunk, encode it, write it out, and go on to the next chunk. Obviously the last chunk will probably be shorter, but encoding it is still independent of the rest.
?>
Conversely, each 76-character MIME-formatted line (not counting the trailing CRLF) contains exactly enough data for 57 bytes of output without needing to retain leftover bits that need prepending to the next line. What that means is that each line can be decoded independently of the others, and the decoded chunks can then be concatenated together or written out sequentially. However, this does make the assumption that the encoded data really is MIME-formatted; without that assurance it is necessary to accept that the base64 data won’t be so conveniently arranged.
A function I’m using to return local images as base64 encrypted code, i.e. embedding the image source into the html request.
This will greatly reduce your page load time as the browser will only need to send one server request for the entire page, rather than multiple requests for the HTML and the images. Requests need to be uploaded and 99% of the world are limited on their upload speed to the server.
base64_decode
(PHP 4, PHP 5, PHP 7, PHP 8)
base64_decode — Декодирует данные, закодированные MIME base64
Описание
Список параметров
Возвращаемые значения
Возвращает декодированные данные или false в случае возникновения ошибки. Возвращаемые данные могут быть бинарными.
Примеры
Пример #1 Пример использования base64_decode()
Результат выполнения данного примера:
Смотрите также
User Contributed Notes 17 notes
If you want to save data that is derived from a Javascript canvas.toDataURL() function, you have to convert blanks into plusses. If you do not do that, the decoded data is corrupted:
Base64 for URL parameters/filenames, that adhere to RFC 4648.
Defaults to dropping the padding on encode since it’s not required for decoding, and keeps the URL free of % encodings.
The base64-decoding function is a homomorphism between modulo 4 and modulo 3-length segmented strings. That motivates a divide and conquer approach: Split the encoded string into substrings counting modulo 4 chars, then decode each substring and concatenate all of them.
This function supports «base64url» as described in Section 5 of RFC 4648, «Base 64 Encoding with URL and Filename Safe Alphabet»
To follow up on Starson’s post, PHP was changed to no longer treat a space as if it were a plus sign in CVS revision 1.43.2.1, which corresponds to PHP 5.1.0. You can see what happened with a diff to branch point 1.43 at:
The CVS log indicates that this change was made to fix bug #34214 (base64_decode() does not properly ignore whitespace).
It would seem from the comment preceding the code which was removed that the treatment of the space as if it were the plus sign was actually intentional at one time:
When Base64 gets POSTed, all pluses are interpreted as spaces.
This line changes them back. It’s not exactly the Base64 spec,
but it is completely compatible with it (the spec says that spaces
are invalid). This will also save many people considerable
headache.
However, RFC 3548 states that characters not in the Base64 alphabet should either be ignored or cause the implementation to reject the encoding and RFC 2045 says they should be ignored. So the original code was unfortunately not fully compatible with the spec or other implementations. It may have also masked problems with code not properly escaping POST variables.
Как PDF, полученный в Base64-строке открыть и распечатать?
Что я получаю: и сервер и console.log(data) выдают одинаковую строку, и с помощью онлайн декодеров base64 тоже проверил получил желанный pdf файл.
Теперь мне надо этот полученный байт-код распечатать и вот тут получаю не то, что получил в качестве данных, а всю страницу. Что делаю не так?
2 ответа 2
РЕШЕНИЕ:
Современные обозреватели сети имеют ограничения безопасности на открытие всплывающих окон.
Для IE:
Согласно документации IE не поддерживает data:URL protocol для PDF. Поэтому в отличии от остальных для него следующий код работать не будет:
Для остальных обозревателей сети:
Для того, чтобы всплывающие окна открывались надо в адресной строке нажать на кнопку-оповещении о всплывающих окнах и выбрать выпадающее меню «Всегда разрешать всплывающие окна с «адрес в сети»». Такая кнопка появляется лишь тогда, если вы ещё такую кнопку для данной страницы не нажимали.
Этот код здесь через snippet не работает из-за ограничений в snippet. Пользователь @Other поделился поэтому ссылкой на этот пример на jsfiddle.net.
Обратите внимание на то, что открытие в текущем окне при помощи перемены window.location или с помощью window.open вам не подойдёт, т.к. распечатать в этих окнах уже не получится, т.к. они в этом случае перезаписываются открываемой страницей.
Можете также посмотреть: PDF Reader на JavaScript от Мozilla. Но для этого нужен уже отдельный вопрос.