I am having the following emoji in a PHP string variable
$emoji = "\u{1F9D1}\u{1F4AC}";
echo $emoji;
This code above will print the following emoji.
🧑💬
I wanted to embed these emojis inside an Email body. For this, I want to convert them to 🧑💬 so that I can place them in the Email body and they will show up correctly.
How do I do this in PHP?
$foo = preg_replace('#\\\u\{(.*?)\}#', '&#x$1;', $emoji);
\u needs to be escaped because it has special meaning in a regular expression, and since the backslash also has special meaning in PHP text literals, we need three of them here.
{ and } also have special meaning, so they need to get escaped with a single backslash.
(.*?) matches everything (expect newlines), ? makes it ungreedy.
I added an ; at the end in the replacement - browsers are fault tolerant when it’s missing, but it is technically required by HTML syntax.
And the “other direction”, as requested:
$emojihtml = '🧑💬';
$bar = preg_replace('~&#x(.*?);~', '\u{$1}', $emojihtml);
(I used ~ for the regex delimiters here, because # is part of what we want to match, saves on escaping.)
Related
I have an issue. I'm trying to write a string with ASCII text like this: '/\'. But whenever I do that the backslash screws up the code by canceling out the quote defining it a string therefore screwing it up. Is there anyway to cancel out the backslash so it doesn't cancel out the quote? Thanks guys!
The \ is special character, that says: 'The next character has special meaning'.
So if you want to dispaly \ you should write... \\ to get one \ in output
It would be very helpful to show what you have tried, but this will produce the exact output you requested (as shown by SO)
echo '\'/\\' . "'\n" ;
'/\'
It should also give you an idea of how backslash escaping works in different types of strings.
A great solution when writing stuff like that is HEREDOC. Inside a heredoc block you don't need to worry about escaping anything, it will just be text.
For example:
echo <<<TEXT
/|\/|\/|\/|\/|\/|\/|\/|\/|\/|\
TEXT;
There is one catch. PHP will break if you don't align the echo at the start of the line, or if the TEXT; is not aligned at the start of the line.
Heredoc can also be assigned to a variable, like so:
$var = <<<SOME_MORE_TEXT
/|\/|\/|\/|\/|\/|\/|\/|\/|\/|\
SOME_MORE_TEXT;
Finally, HEREDOC preserves tabs and spaces. Which also might come in handy when doing ASCII art.
Refer to: http://php.net/manual/en/language.types.string.php for more information.
You only need to escape the final one when using single quotes.
$var = 'backslash\backslash\backslash\\';
// output is:
// backslash\backslash\backslash\
if im not wrong \n representation means that a newline as <br> .But when i use <br> or another tags they work properly but escape sequences.
example
echo "write somethings<br>";
echo "about coding";
above example works fine but when i try to use escape sequences none of them are not working
echo "write something\n";
echo "about coding";
it's just an example for newline character and the other escaping characters dont work as \n.What is the real logic on this case?
\n and other similar escape sequences are not part of HTML. You should use HTML escape sequences. These can be found here: http://www.theukwebdesigncompany.com/articles/entity-escape-characters.php
So only your <br> tag works but \n is not
No, this is an example of HTML rules.
Putting \n in a PHP string and then outputting it as HTML will put a new line character in the HTML source code. It's just line pressing return when writing raw HTML.
HTML puts no special meaning on the new line character (at least outside of script elements and elements with various non-default values of the CSS white-space property) and treats it like any other white space character.
<br>, on the other hand, is a line break element (but usually an indication that you should be using a block level element around the content instead).
HTML ignores carriage return and linefeed characters, treating them as whitespace. If you want to use display a string formatted with "\n" you can use nl2br to convert it, e.g.
echo nl2br("this is on\ntwo lines");
If you look at this in the browser it wont work : browser knows only HTML for display (<br>) but not escape like \n or \r
I am trying to send a GET message that contains strings with ampersands and can't figure how to escape the ampersand in the URL.
Example:
http://www.example.com?candy_name=M&M
result => candy_name = M
I also tried:
http://www.example.com?candy_name=M\&M
result => candy_name = M\\
I am using URLs manually, so I just need the correct characters.
I can't use any libraries. How can it be done?
They need to be percent-encoded:
> encodeURIComponent('&')
"%26"
So in your case, the URL would look like:
http://www.mysite.com?candy_name=M%26M
This does not only apply to the ampersand in URLs, but to all reserved characters. Some of which include:
# $ & + , / : ; = ? # [ ]
The idea is the same as encoding an &in an HTML document, but the context has changed to be within the URI, in addition to being within the HTML document. So, the percent-encoding prevents issues with parsing inside of both contexts.
The place where this comes in handy a lot is when you need to put a URL inside of another URL. For example, if you want to post a status on Twitter:
http://www.twitter.com/intent/tweet?status=What%27s%20up%2C%20StackOverflow%3F(http%3A%2F%2Fwww.stackoverflow.com)
There's lots of reserved characters in my Tweet, namely ?'():/, so I encoded the whole value of the status URL parameter. This also is helpful when using mailto: links that have a message body or subject, because you need to encode the body and subject parameters to keep line breaks, ampersands, etc. intact.
When a character from the reserved set (a "reserved character") has
special meaning (a "reserved purpose") in a certain context, and a URI
scheme says that it is necessary to use that character for some other
purpose, then the character must be percent-encoded. Percent-encoding
a reserved character involves converting the character to its
corresponding byte value in ASCII and then representing that value as
a pair of hexadecimal digits. The digits, preceded by a percent sign
("%") which is used as an escape character, are then used in the URI
in place of the reserved character. (For a non-ASCII character, it is
typically converted to its byte sequence in UTF-8, and then each byte
value is represented as above.) The reserved character "/", for
example, if used in the "path" component of a URI, has the special
meaning of being a delimiter between path segments. If, according to a
given URI scheme, "/" needs to be in a path segment, then the three
characters "%2F" or "%2f" must be used in the segment instead of a raw
"/".
http://en.wikipedia.org/wiki/Percent-encoding#Percent-encoding_reserved_characters
Try using http://www.example.org?candy_name=M%26M.
See also this reference and some more information on Wikipedia.
I would like to add a minor comment to Blender's solution.
You can do the following:
var link = 'http://example.com?candy_name=' + encodeURIComponent('M&M');
That outputs:
http://example.com?candy_name=M%26M
The great thing about this it does not only work for &, but for any especial character.
For instance:
var link = 'http://example.com?candy_name=' + encodeURIComponent('M&M?><')
Outputs:
"http://example.com?candy_name=M%26M%3F%3E%3C"
You can use the % character to 'escape' characters that aren't allowed in URLs. See RFC 1738.
A table of ASCII values is given on the Wikipedia page.
You can see & is 26 in hexadecimal - so you need M%26M.
This may help if someone want it in PHP
$variable ="candy_name=M&M";
$variable = str_replace("&", "%26", $variable);
If you can't use any libraries to encode the value,
http://www.urlencoder.org/ or http://www.urlencode-urldecode.com/ or ...
Just enter your value "M&M", not the full URL ;-)
You can rather pass your arguments using this encodeURIComponent function so you don't have to worry about passing any special characters.
data: "param1=getAccNos¶m2="+encodeURIComponent('Dolce & Gabbana') OR
var someValue = 'Dolce & Gabbana';
data : "param1=getAccNos¶m2="+encodeURIComponent(someValue)
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent
Every time I try to echo a string there is no new line. I how can I make a newline when calling echo in php using the $_GET?
here is my code:
<?php
$text = "Hello world";
$text2 = $_GET['msg'];
echo $text2
?>
and this is what I enter in the url:
http://localhost/hello.php?msg=hello%0Dworld
or this one:
http://localhost/hello.php?msg=hello%0Aworld
and even this one:
http://localhost/hello.php?msg=hello%0D%0Aworld
The echo has to be a newline please don't say I should use a different method than $_GET. It has to be $_GET
While performing your exercises you are creating an HTML page.
HTML is a special markup language, which renders according to set of rules, some of them are:
<> characters has a special meaning of control structures named tags
all newline characters are ignored
to make a newline on the page, one have to use suitable tag - such as <br>, <p> or whatever.
So, to make a newline appear on your page, you have to convert newline characters to tags. Either use nl2br() function to get a <br /> tag or str_replace() if you want any other one
Be aware that echoing any request variables without validating them is a considerable security risk! If you want to publish any application with this code it needs to be redesigned.
As common sense states, the conversion from urlencoded to the corresponding character is automatically done by php, but HTML does not render such characters, so you either need to convert them into linebreaks or enclose the message in <pre> tags.
I am saving C++ code from a textarea of an HTML form using PHP.
The problem is if my code is like below,
printf("%d\n");
printf("%d\n");
the code that is saved to the file is like this:
printf(\"%d\\n\");\nprintf(\"%d\\n\");
I want the original code to be saved in the file. If I use,
$sourceCode = str_replace('\n',"\n", $sourceCode);
$sourceCode = str_replace('\"',"\"", $sourceCode);
the result is like below (saved in the file):
printf("%d\
");printf("%d\
");
It is clear that replacing \n in the source code replaces all the HTML created \n along with the \n that user gave as input (the original text). The only difference is user's input has an additional \ before the \n, that is \\n.
How can I resolve the problem such that only the implicit escape characters will be replaced, but the explicit escape characters, that the user wrote himself, will not be changed?
As mentioned by KenB, we need to see the PHP code that you are using to process the form input.
Processing Form Input
It looks to me like addslashes has been used on the form input.
If you are doing that in your code, don't. This is not the proper way to process form input. Instead, you should use the correct function (such as htmlspecialchars or mysqli_real_escape_string) to escape the input before you use it. Read about addslashes.
If you are using an older version of PHP where magic_quotes_gpc is on by default, then you should fix that. Read about 'Disabling Magic Quotes'.
Stripping Out the Slashes
If you have no control over the code that is adding the slashes, then you can remove them with a simple PHP function called stripslashes.
$sourceCode = stripslashes($sourceCode);
Read about stripslashes.
Understanding Escape Sequences
Your str_replace code shows a lack of understanding about escape sequences and/or a lack of understanding about single vs double quotes.
In the following code, a literal \n is replaced with a line break. With the double quotes, PHP interprets the \n as an escape sequence rather than a literal string.
$sourceCode = str_replace('\n',"\n", $sourceCode);
What you want is to replace a literal \\n with a literal \n. Note that to specify a literal backslash it must be doubled; hence the triple backslash you see below.
$sourceCode = str_replace('\\\n', '\n', $sourceCode);
And although this next line accomplishes what you wanted...
$sourceCode = str_replace('\"',"\"", $sourceCode);
...it could have been written differently. The following code is easier to read, saves you having to escape the literal ", and doesn't require PHP to interpret the string.
$sourceCode = str_replace('\"', '"', $sourceCode);
I've given the above code as examples to explain how PHP interprets escapes sequences, but don't use them. Either avoid adding the slashes in the first place or strip them using the proper function, as explained in the first part of this answer.
Read more about escape sequences and quoting strings.
The Literal \n Between Lines
I'm not sure what you are doing to add the literal \n between the lines. We'd need to see your code. But to remove it after the fact, you could try the following
$sourceCode = str_replace(';\n', ";\n", $sourceCode);
Of course, then you'd likely need to correct other C++ end-of-line sequences. So it is better to not add it in the first place.