mysql and encoding - php

I moved my php application to the new server. i use mysql5 db. When i'm Updating or Inserting something to db, every " and - sign changed to ?. I use SET NAMES UTF8 and SET CHARACTER SET but it don't work. Any ideas?

SET NAMES UTF8 should be used on every page, when selecting as well as when updating or inserting.
actually this query must be used every time you connect to the database. just add it to connect code.

You need UTF-8 all the way through to make smart quotes and dashes (“”—) and other non-ASCII characters work reliably:
(1) Ensure that the browser sends you characters encoded to UTF-8. Do this by declaring the page that includes the form to be UTF-8:
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8">
...
(Ignore <form accept-encoding>, which doesn't work right in IE.)
(2) PHP deals with raw bytes and doesn't care what encoding they're in, but the database does care, so you have to tell it what encoding the bytes from PHP are coming in. This is what SET NAMES is doing, though mysql_set_charset may be preferable.
(3) Once the proper characters have reached the database, it'll need to store them in a Unicode encoding to make sure all characters can fit. Each column can have a different encoding, but you can use DEFAULT CHARACTER SET utf8 when you CREATE table to make all the text columns in it use UTF-8. You can also set the default character set for a database or the whole server to utf8 if you prefer.
If you have already CREATE​d the tables and they a non-UTF-8 collation, you'll have to recreate or alter the tables. You can check the current collation using SHOW FULL COLUMNS FROM sometable;.
(4) Make sure you HTML-encode text you output from PHP using htmlspecialchars() and not htmlentities(), which by default will mess up non-ASCII characters.
[You can, as an alternative to (2) and (3), just use the default Latin-1 encoding for the connection and the table storage, but put UTF-8 bytes in it nonetheless. The disadvantage of this approach is that it'll look wrong to other tools looking at the database, and lower/upper case characters won't compare against each other in the expected case-insensitive way.]

My guess is you are pasting from some text editor which is transforming the " into an angled pretty quote, and transforming your - into an mdash, which is causing both to be represented as ?.
While you set your database to accept UTF8 characters, you probably did not set your webserver/PHP to accept those characters. Try playing with mbstring functions, but check to make sure you arent using the slanted quotes or dashes.

Related

Special characters in mySQL (and php) - THE BASICS

I am confused! Recently my webhotel updated php and now my old tables render special characters differently (wrongly).
Both my tables and my input/output-php-pages are set to utf-8 and since this update, also the inputs from php are treated differently; now my special characters are being utf-8-encoded as they enter the database. So since this change, when I review tables within phpMyAdmin, the old inserts have the original (non-encoded) special characters - the new posts have utf-8-encoded charcters (also special).
So what I would like to do is rewrite input and output to insert and show non-encoded characters - but I am not sure if this is possible without skipping utf-8 entirely (in php and mySQL). But is there an utf-8- way to submit non-encoded characters?
AND - perhaps more fundamentally - I need to understand what the possible downsides are. I am using Danish characters in and out and I'm not going to use any other language (for this project). So if it IS possible to insert and output non-encoded characters using utf-8 - am I then going to have unexpected/destructive issues?
I have read a lot of posts regarding php/mySQL/special characters but I haven't seen this angle on the issue yet. Hope I am not duplicating
I hope not because it has been working very nicely until the update.
Even if you are using only Danish characters, you may as well go utf8 all the way.
There are many places where the encoding needs to be stated:
The at the top of the html
The columns in the database (column CHARACTER SET defaults from table, which defaults from database)
The encoding in your PHP code.
When you CREATE TABLE, tack on DEFAULT CHARACTER SET utf8. If you have existing tables, without that, speak up; we may need to deal with them.
If you want Danish collation, the specify COLLATION utf8_danish_ci, too. Then (if I recall correctly), aa will sort after z.
(The default is utf8_general_ci, which won't do that sorting.)
Figure out what encoding you have (or can get) in your php code. If you have some text with accents in it, do this:
$hex = unpack('H*', $text);
echo implode('', $hex)
If you have utf8, å will be C3A5, for latin1 it will be E5.
Regardless of what encoding in in the tables, you must call set_charset('utf8') or set_charset('latin1') depending on what encoding is in the data in PHP. MySQL will gladly transcode between latin1 and utf8 as things are passed between PHP and MySQL. For different APIs:
⚈ mysql: mysql_set_charset('utf8');
⚈ mysqli: $mysqli_obj->set_charset('utf8');
⚈ PDO: $db = new PDO('dblib:host=host;dbname=db;charset=UTF-8', $user, $pwd);
For much more info, see http://mysql.rjweb.org/doc.php/charcoll .

Using accented characters in PHP

I am trying to upload text into my database. I keep getting encoded text when user input certain characters. For example, if the user inputs "Jalapeño" I end up getting "Jalape%C3%B1o" in my database.
I know this is because the "ñ" is being read as "%C3%B1"...
I am not exactly sure how to go about converting all of the potential accented characters, I have looked at rewurldecode and others, but am wondering if there is a quick solution here. Any recommendations would be wonderful. Thank you!
Make sure your database uses the right character set and collation (usually you'll want UTF-8). Also make sure you you set the connection character set and sent the right headers.
e.g. mysql:
mysql_connect();
mysql_set_charset("utf8");
header('Content-Type: text/html; charset=utf-8');
You could also use htmlentities to convert the special characters into HTML entities, but you'll still need to make sure your database collation and connection settings are correct.
Your character is urlencoded. To display it properly, you have to decode it. But url encoding is not meant to be used when saving data in the database. As dtech points, you have to use utf8 character set.

PHP charset accents issue

I have a form in my page for users to leave a comment.
I'm currently using this charset:
meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1"
but retrieveving the comment from DB accents are not displaying correct ( Ex. è =>è ).
Which parameters should i care about for a correct handling of accents?
SOLVED
changed meta tag to charset='utf-8'
changed character-set Mysql (ALTER TABLE comments CONVERT TO CHARACTER SET utf-8)
changed connection character-set both when inserting records and retrieving ($conn->query('SET NAMES utf8'))
Now accents are displaying correct
thanks
Luca
Character sets can be complicated and pain to debug when it comes to LAMP web applications. At each of the stages that one piece of software talks to another there's scope for incorrect charset translation or incorrect storage of data.
The places you need to look out for are:
- Between the browser and the web server (which you've listed already)
- Between PHP and the MySQL server
The character you've listed look like normal a European character that will be included in the ISO-8859-1 charset.
Things to check for:
even though you're specifying the character set in a meta header have a look in your browser to be sure which character set the browser is actually using. If you've specified it the browser should use that charset to render/view the page but in cases I've seen it attempting to auto-detect the correct charset and failing. Most browsers will have an "encoding" menu (perhaps under "view") that allows you to choose the charset. Ensure that it says ISO-8859-1 (Western European).
MySQL can happily support character set conversion if required to but in most cases you want to have your tables and client connection set to use the same encoding. When configured this way MySQL won't attempt to do any encoding conversion and will just write the data you input byte for byte into the table. When read it'll come out the same way byte for byte.
You've not said if you're reading data from the database back out with the same web-app or with some other client. I'd suggest you try to read it out with the same web application and using the same meta charset header (again, check the browser is really setting it) and see what is displayed in the browser.
To debug these issues requires you to be really sure about whether the client/console you're using is doing any conversion too, the safest way is sometimes to get the data into a hex editor where you can be sure that nothing else is messing around with any translation.
If it doesn't look like it's a browser-side problem please can you include the output of the following commands against your database:
Run from a connection that your web-app makes (not from some other MySQL client):
SHOW VARIABLES LIKE 'character_set%';
SHOW VARIABLES LIKE 'collation%';
Run from any MySQL client:
SHOW CREATE TABLE myTable;
(where myTable is the table you're reading/writing data from/to)
The ISO-8859-1 character set is for Latin characters only. Try UTF-8, and make sure that the database these characters are coming from are also UTF-8 columns.

How do browsers/PHP handle characters outside the set characterset?

I'm looking into how characters are handled that are outside of the set characterset for a page.
In this case the page is set to iso-8859-1, and the previous programmer decided to escape input using htmlentities($string,ENT_COMPAT). This is then stored into Latin1 tables in Mysql.
As the table is set to the same character set as the page, I am wondering if that htmlentities step is needed.
I did some experiments on http://floris.workingweb.nl/experiments/characters.php and it seems that for stuff inside Latin1 some characters are escaped, but for example with a Czech name they are not.
Is this because those characters are outside of Latin1? If so, then the htmlentities can be removed, as it doesn't help for stuff outside of Latin1 anyway, and for within Latin1 it is not needed as far as I can see now...
htmlentities only translates characters it knows about (get_html_translation_table(HTML_ENTITIES) returns the whole list), and leaves the rest as is. So you're right, using it for non-latin data makes no sense. Moreover, both html-encoding of database entries and using latin1 are bad ideas either, and I'd suggest to get rid of them both.
A word of warning: after removing htmlentities(), remember that you still need to escape quotes for the data you're going to insert in DB (mysql_escape_string or similar).
He could have used it as a basic safety precaution, ie. to prevent users from inserting HTML/Javascript into the input (because < and > will be escaped as well).
btw If you want to support Eastern and Western European languages I would suggest using UTF-8 as the default character encoding.
Yes
though not because Czech characters are outside of Latin1 but because they share the same places in the table. So, database take it as corresponding latin1 characters.
using htmlentities is always bad. the only proper solution to store different languages is to use UTF-8 charset.
Take note that htmlentities / htmlspecialchars have a 3rd parameter (since PHP 4.1.0) for the charset. ISO-8859-1 is the default so if you apply htmlentities without a 3rd parameter to a UTF-8 string for example, the output will be corrupted.
You can detect & convert the input string with mb_detect_encoding and mb_convert_encoding to make sure the input string match the desired charset.

php mysql character set: storing html of international content

i'm completely confused by what i've read about character sets. I'm developing an interface to store french text formatted in html inside a mysql database.
What i understood was that the safe way to have all french special characters displayed properly would be to store them as utf8. so i've created a mysql database with utf8 specified for the database and each table.
I can see through phpmyadmin that the characters are stored exactly the way it is supposed to. But outputting these characters via php gives me erratic results: accented characters are replaced by meaningless characters. Why is that ?
do i have to utf8_encode or utf8_decode them? note: the html page character encodign is set to utf8.
more generally, what is the safe way to store this data? Should i combine htmlentities, addslashes, and utf8_encode when saving, and stripslashes,html_entity_decode and utf8_decode when i output?
MySQL performs character set conversions on the fly to something called the connection charset. You can specify this charset using the sql statement
SET NAMES utf8
or use a specific API function such as mysql_set_charset():
mysql_set_charset("utf8", $conn);
If this is done correctly there's no need to use functions such as utf8_encode() and utf8_decode().
You also have to make sure that the browser uses the same encoding. This is usually done using a simple header:
header('Content-type: text/html;charset=utf-8');
(Note that the charset is called utf-8 in the browser but utf8 in MySQL.)
In most cases the connection charset and web charset are the only things that you need to keep track of, so if it still doesn't work there's probably something else your doing wrong. Try experimenting with it a bit, it usually takes a while to fully understand.
I strongly recomend to read this article "The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!)" by Joel Spolsky, to understand what are you doing and why.
It is useful to consider the PHP-generated front end and the MySQL backend separate components. MySQL should not have to worry about display logic, nor should PHP assume that the backend does any sort of preprocessing on the data.
My advice would be to store the data in plain characters using utf8 encoding, and escape any dangerous characters with MySQLs methods.
PHP then reads the utf8 encoded data from database, processes them (with htmlentities(), most often), and displays it via whichever template you choose to use.
Emil H. correctly suggested using
SET NAMES utf8
which should be the first thing you call after making a MySQL connection. This makes the MySQL treat all input and output as utf8.
Note that if you have to use utf8_encode or utf8_decode functions, you are not setting the html character encoding correctly. It is easiest to require that every component of your system uses utf8, since that way you should never have to do manual encoding/decoding, which can cause hard to track issues later on.
In adition to what Emil H said, you also need this in your page head tag:
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />

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