My next web application project will make extensive use of Unicode. I usually use PHP and CodeIgniter however Unicode is not one of PHP's strong points.
Is there a PHP tool out there that can help me get Unicode working well in PHP?
Or should I take the opportunity to look into alternatives such as Python?
PHP can handle unicode fine once you make sure to encode and decode on entry and exit. If you are storing in a database, ensure that the language encodings and charset mappings match up between the html pages, web server, your editor, and the database.
If the whole application uses UTF-8 everywhere, decoding is not necessary. The only time you need to decode is when you are outputting data in another charset that isn't on the web. When outputting html, you can use
htmlentities($var, ENT_QUOTES, 'UTF-8');
to get the correct output. The standard function will destroy the string in most cases. Same goes for mail functions too.
http://developer.loftdigital.com/blog/php-utf-8-cheatsheet is a very good resource for working in UTF-8
One of the Major feature of PHP 6 will be tightly integrated with UNICODE support.
Implementing UTF-8 in PHP 5.
Since PHP strings are byte-oriented, the only practical encoding scheme for Unicode text is UTF-8. Tricks are [Got it from PHp Architect Magazine]:
Present HTML pages in UTF-8
Convert PHP scripts to UTF-8
Convert the site content, back-end databases and the like to UTF-8
Ensure that no PHP functions corrupt the UTF-8 text
Check out http://www.gravitonic.com/talks/ PHP UTF 8 Cheat Sheet
PHP is mostly unaware of chrasets and treats strings as bytestreams. That's not much of a problem really, but you'll have to do a bit of work your self.
The general rule of thumb is that you should use the same charset everywhere. If you use UTF-8 everywhere, then you're 99% there. Just make sure that you don't mix charsets, because then it gets really complicated. The only thing that won't work correct with UTF-8, is string manipulation, which needs to operate on a character level. Eg. strlen, substr etc. You should use UTF-8-aware versions in place of those. The multibyte-string extension gives you just that.
For a checklist of places where you need to make sure the charset is set correct, look at:
http://developer.loftdigital.com/blog/php-utf-8-cheatsheet
For more information, look at:
http://www.phpwact.org/php/i18n/utf-8
Related
Example :
$fire = '🔥';
I know PHP 5+ supports this functionality natively but is it best practice or should I be storing them using their codepoints instead and if so, why?
As far as your editor and the PHP compiler are concerned, it's all just text, and '🔥' is no different from 'fire' or 'Φωτιά'.
When PHP runs, it will read the bytes in from the file and put them in memory, without caring what they mean. This leads to the most likely problem you'll have: if you save the file in your text editor as UTF-16, and then echo the string to a browser telling it that it's UTF-8, the browser won't show the right thing. But that's easily avoided by making sure your editor always uses UTF-8, and your output headers tell the browser that's what you're using.
If you don't trust your editor to do that, and you're running PHP7, you could write it in the escaped notation "\u{1f525}", but when it runs, the same bytes will end up in memory.
You might have similar problems if you send the text elsewhere - to a database, for instance - and that somewhere else doesn't know to handle it as UTF-8. How you write the string in your source file won't make any difference to that, though, that's just a case of making sure everything is configured to match.
Note: you don't actually have to use UTF-8 for this, you could use UTF-16, or some other encoding, as long as you're consistent; but UTF-8 is by far the most common these days, particularly on the web.
I have read several things about this topic but still I have doubts I want to share with the community.
I want to add a complete utf-8 support to the application I developed, DaDaBIK; the application can be used with different DBMSs (such as MySQL, PostgreSQL, SQLite). The charset used in the databases can be ANY. I cant' set or assume the charset.
My approach would be convert, using iconv functions, everything i read from the db in utf-8 and then convert it back in the original charset when I have to write to the DB. This would allow me to assume I'm working with utf-8.
The problem, as you probably know, is that PHP doesn't support utf-8 natively and, even assuming to use mbstring, there are (according to http://www.phpwact.org/php/i18n/utf-8) several PHP functions which can create problems with utf-8 and DON't have an mbstring correspondance, for example the PREG extension, strcspn, trim, ucfirst, ucwords....
Since I'm using some external libraries such as adodb and htmLawed I can't control all the source code...in those libraries there are several cases of usage of those functions....do you have any advice about? And above all, how very popular applications like wordpress and so on are handling this (IMHO big) problem? I doubt they don't have any "trim" in the code....they just take the risk (data corruption for example) or there is something I can't see?
Thanks a lot.
First of all: PHP supports UTF-8 just fine natively. Only a few of the core functions dealing with strings should not be used on multi-byte strings.
It entirely depends on the functions you are talking about and what you're using them for. PHP strings are encoding-less byte arrays. Most standard functions therefore just work on raw bytes. trim just looks for certain bytes at the start and end of the string and trims them off, which works perfectly fine with UTF-8 encoded strings, because UTF-8 is entirely ASCII compatible. The same goes for str_replace and similar functions that look for characters (bytes) inside strings and replace or remove them.
The only real issue is functions that work with an offset, like substr. The default functions work with byte offsets, whereas you really want a more intelligent character offset, which does not necessarily correspond to bytes. For those functions an mb_ equivalent typically exists.
preg_ supports UTF-8 just fine using the /u modifier.
If you have a library which uses, for instance, substr on a potential multi-byte string, use a different library because it's a bad library.
See What Every Programmer Absolutely, Positively Needs To Know About Encodings And Character Sets To Work With Text for some more in-depth discussion and demystification about PHP and character sets.
Further, it does not matter what the strings are encoded as in the database. You can set the connection encoding for the database, which will cause it to convert everything for you and always return you data in the desired client encoding. No need for iconverting everything in PHP.
I have an open source PHP website and I intend to modify/translate (mostly constant strings) it so it can be used by Japanese users.
The original code is PHP+MySQL+Apache and written in English with charset=utf-8
I want to change, for example, the word "login" into Japanese counterpart "ãƒã‚°ã‚¤ãƒ³" etc
I am not sure whether I have to save the PHP code in utf-8 format (just like Python)?
I only have experience with Python, so what other issues I should take care of?
If it's in the file, then yes, you will need to save the file as UTF-8.
If it's is in the database, you do not need to save the PHP file as UTF-8.
In PHP, strings are basically just binary blobs. You will need to save the file as UTF-8 so the correct bytes are read in. In theory, if you saved the raw bytes in an ANSI file, it would still be output to the browser correctly, just your editor would not display it correctly, and you would run the risk of your editor manipulating it incorrectly.
Also, when handling non-ANSI strings, you'll need to be careful to use the multi-byte versions of string manipulation functions (str_replace will likely botch a utf-8 string for example).
If the file contains UTF-8 characters then save it with UTF-8. Otherwise you can save it in any format. One thing you should be aware of is that the PHP interpreter does not support the UTF-8 byte order mark so make sure you save it without that.
I'm sorry you have to use PHP after using Python.
PHP has no concept of character sets: all strings are binary, even in parsed php code, so if you include a UTF-8 multibyte character in a php string, make sure the bytes in the code file are UTF-8 bytes.
You will need to be extremely careful with the use of string functions at all levels of your application. You also need to make sure your MySQL connection is set to use UTF-8 (using SET NAMES or the charset dsn parameter in later versions of PDO), and that your mysql string column datatypes use utf-8 storage.
This has been always a problem for me , Character problem . I always tried to solve my problem with little patches , actually this never solves my problem in reality.So I am looking for very strong solution to solve all these problems.I want to learn how big apps(facebook , google, other multi lingual ajax apps and apis) solve this problem. I want a solution which will solve all my character encoding , etc problems.I use php, mysql, html and javascript to create my application , so the solution should solve all problems or all these languages together.If you write full configuration this is perfect , but if there is a long long document , I can read it to . I need help . Thank you . I can not transfer string(text) correctly through all these languages
Also I pull data from external apis.How should I take care of them
It's pretty easy if you just stick to using Unicode everywhere.
set MySQL table encodings to UTF-8
make sure you're talking to the database in UTF-8 by running SET NAMES utf8
save all your source code in UTF-8
when manipulating strings in PHP which may contain UTF-8 characters, use the mb_ functions
send HTTP Content-Type headers denoting that the content is in UTF-8
Javascript is intrinsically UTF-8, so you should have no worries there
The thing is that different technologies default to different character encodings. Unfortunately strings do not have implicit encoding metadata attached, they're just sequences of bytes. Unless being told, the receiver of a string can only make a best guess what encoding that sequence is supposed to be in. Whenever connecting two pieces of anything, you need to make sure they're using the same encoding (or you need to specifically convert from one encoding to the other). Always assume that you have to define the encoding somewhere, how exactly that needs to be done depends on the technology.
About 2 years ago I made the mistake of starting a large website using iso-8859-1. I now am having issues with some characters, especially when sending data to the server using ajax. Because of this, I would like to switch to using UTF-8.
What issues do you see coming from this? I know I would have to search the site to look for characters that need to be changed from a ? to their real characters. But, are there any other risks in doing this? Has anyone done this before?
The main difficulty is making sure you've checked that all the data paths are UTF-8 clean:
Is your site DB-backed? If so, you'll need to convert all the tables to UTF-8 or some other Unicode encoding, so sorting and text searching work correctly.
Is your site using some programming language for dynamic content? (PHP, mod_perl, ASP...?) If so, you'll have to make sure the particular language interpreter you're using fully understands some form of Unicode, work out the conversions if it isn't using UTF-8 natively — UTF-16 is next most common — and check that it's configured to use UTF-8 on its output to the web server.
Does your site have some kind of back-end app server? Does it use UTF-8 for its text outputs?
There are at least three different places you can declare the charset for a web document. Be sure you change them all:
the HTTP Content-Type header
the <meta http-equiv="Content-Type"> tag in your documents' <head>
the <?xml> tag at the top of the document, if using XHTML Strict
All this comes from my experiences a years ago when I traced some Unicode data through a moderately complex N-tier app, and found conversion chains like:
Latin-1 → UTF-8 → Latin-1 → UTF-8
So, even though the data ended up in the browser claiming to be "UTF-8", the app could still only handle the subset common with Latin-1.
The biggest reason for those odd conversion chains was due to immature Unicode support in the tooling at the time, but you can still find yourself messing with ugliness like this if you're not careful to make the pipeline UTF-8 clean.
As for your comments about searching out Latin-1 characters and converting files one by one, I wouldn't do that. I'd build a script around the iconv utility found on every modern Linux system, feeding in every text file in your system, explicitly converting it from Latin-1 to UTF-8. Leave no stone unturned.
Such a change touches (nearly) every part of your system. You need to go through everything, from the database to the PHP to the HTML to the web browser.
Start a test site and subject it to some serious testing (various browsers on various platforms doing various things).
IMO it's important to actually get familiar with UTF-8 and what it means for software. A few quick points:
PHP is mostly byte-oriented. Learn the difference between characters and code points and bytes, and between UTF-8 and Unicode.
UTF-8 is well-designed. For instance, given two UTF-8 strings, a byte-oriented strstr() will still function correctly.
The most common problem is treating a UTF-8 string as ISO-8859-1 and vice versa - you may need to add documentation to your functions stating what kind of encoding they expect, to make these sorts of errors less likely. A variable naming convention for your strings (to indicate what encoding they use) may also help.