How to remove escaping in PHP? - php

I have this URL parameter:
KKe%7bZoE_%24g)tjm%40
When I put it into a variable and echo it, the result is:
KKe{ZoE_$g)tjm#
How to avoid that?

Data in $_GET is already URL-decoded. If you require the original string, get it from $_SERVER['QUERY_STRING']. Note that you will have to process the query string yourself though, including breaking down the individual components.
Alternatively, use rawurlencode($_GET[..]) to re-encode the value; which may or may not produce slightly differently encoded values than you originally got.

Test it with html_entity_decode - it helpt me a lot with my inputs.

If the string is not shown as it is, you have urlencode() or htmlentities() somewhere in your code. Check that, you shouldn't encode html entities before echoing if you want the string to be intact.

Related

PHP Escape a string if it hasn't already been escaped with entities

I'm using a 3rd party API that seems to return its data with the entity codes already in there. Such as The Lion’s Pride.
If I print the string as-is from the API it renders just fine in the browser (in the example above it would put in an apostrophe). However, I can't trust that the API will always use the entities in the future so I want to use something like htmlentities or htmlspecialchars myself before I print it. The problem with this is that it will encode the ampersand in the entity code again and the end result will be The Lion’s Pride in the HTML source which doesn't render anything user friendly.
How can I use htmlentities or htmlspecialchars only if it hasn't already been used on the string? Is there a built-in way to detect if entities are already present in the string?
No one seems to be answering your actual question, so I will
How can I use htmlentities or htmlspecialchars only if it hasn't already been used on the string? Is there a built-in way to detect if entities are already present in the string?
It's impossible. What if I'm making an educational post about HTML entities and I want to actually print this on the screen:
The Lion’s Pride
... it would need to be encoded as...
The Lion’s Pride
But what if that was the actual string we wanted to print on the string ? ... and so on.
Bottom line is, you have to know what you've been given and work from there – which is where the advice from the other answers comes in – which is still just a workaround.
What if they give you double-encoded strings? What if they start wrapping the html-encoded strings in XML? And then wrap that in JSON? ... And then the JSON is converted to binary strings? the possibilities are endless.
It's not impossible for the API you depend on to suddenly switch the output type, but it's also a pretty big violation of the original contract with your users. To some extent, you have to put some trust in the API to do what it says it's going to do. Unit/Integration tests make up the rest of the trust.
And because you could never write a program that works for any possible change they could make, it's senseless to try to anticipate any change at all.
Decode the string, then re-encode the entities. (Using html_entity_decode())
$string = htmlspecialchars(html_entity_decode($string));
https://eval.in/662095
There is NO WAY to do what you ask for!
You must know what kind of data is the service giving back.
Anything else would be guessing.
Example:
what if the service is giving back & but is not escaping ?
you would guess it IS escaping so you would wrongly interpret as & while the correct value is &
I think the best solution, is first to decode all html entities/special chars from the original string, and then html encode the string again.
That way you will end up with a correctly encoded string, no matter if the original string was encoded or not.
You also have the option of using htmlspecialchars_decode();
$string = htmlspecialchars_decode($string);
It's already in htmlentities:
php > echo htmlentities('Hi&mom', ENT_HTML5, ini_get('default_charset'), false);
Hi&mom
php > echo htmlentities('Hi&mom', ENT_HTML5, ini_get('default_charset'), true);
Hi&mom
Just use the [optional]4th argument to NOT double-encode.

Using variables containing special characters

I am working on a project and a lot of my variables need to contain special characters such as {}[].'"!?/\=+- and many more what is the safest way to pass these variables back and forth between SQL, PHP, and output? and how can I prevent a variable from interfering with my code? Ie:
<?php
echo $var;
echo '$var';
echo "$var";
?>
The best way would be to URL encode your data as soon as it is supplied. Then store it and when you are using it, urldecode it.
Something like
string urlencode ( string $str )
To encode and
string urldecode ( string $str )
To decode. This changes your "special" characters into safe characters.
In PHP, the name of a variable cannot contain special characters (other than the initial dollar sign $ and underscores _). The value of a variable can contain whatever you'd like so long as you follow the rules of defining PHP strings.
The variable values won't interfere with your code. If you're concerned about it interfering with your output HTML, use htmlspecialchars as Rocket Hazmat suggested in the comments.
You can use PDO/MYSQL for isnerting the data into the database..
For converting into html entites you can use htmlchars() function.
An example:
<?php
${'[\*var'} = 1;
echo ${'[\*var'};
https://3v4l.org/5Dr93

Allow certain characters to pass through $_GET?

I wrote a script that when you enter a textbox, it will open an invisible iframe to a .php file with $_GET of what they wrote into the textbox.
However, for example, if I type: '<3' in it, this is what happens.
PHP determins that the $_GET[s] is blank! Users cant put a simple <3 symbol without getting that error.
Another problem is quotes, if I write any quotes, it will end the entire SRC property.
What should I do? Should I do something with javascript, or even PHP? Please let me know!
Thanks!
Use urlencode to encode the inputted string into a valid one for URL use.
Also be very cautious when allowing user input into your PHP script through the URL. Make sure you do proper checks/sanitization, especially if database operations are involved.
It looks like your iframe is generated by JavaScript, so all those answers that include PHP functions are useless. The data isn't even reaching PHP, so how can any PHP function hope to help?
Instead, try using urlencode from PHPJS, since none of JS's functions really handle all cases well, and this makes it easy for you to use PHP's urldecode to retrieve the data.
You need to encode that character as <.
Regarding double quotes, you can use this trick.
attr='Your string can "contain double quotes"'
or
attr="Your string can 'contain double quotes'"
but while specifying variable=values in url, you don't need to user double quotes, you can directly assign the values.
like
url="test.php?var1=123&var2=345"
rest about sending the <3 characters, you can check for url encoding in javascript & PHP whichever applicable!

Make Json parsable by php

I have some weirdly formatted json string which is invalid json, but executes as valid javascript. This means PHP json_decode, will not work.
{
"Devices":{
"Device1":"{ \"Name\"=\>\"AutoTap LDVDS\",\"ID\"=\>\"LDVDSDevice\"}"
}
}
The backslashes are not valid. Is there some way I can escape this string so it can be re-encoded exactly the same as it came in?
Edit I don't care about parsing the messy string at all. It's preventing me from accessing other data. I was doing a simple regex to strip the ugly strings out of the json before parsing it. But now I need to re-encode the result array back into JSON and I want to avoid losing this data. The ugly string should remain exactly the same, as it may be important to some other application that uses this data.
The => comes from ruby object notation in case you are wondering.
Well, it's those weird escaped > that are killing it: \>
I see no reason why you can't str_replace them out of existence safely with a simple:
<?php
$code='{
"Devices":{
"Device1":"{ \"Name\"=\>\"AutoTap LDVDS\",\"ID\"=\>\"LDVDSDevice\"}"
}
}';
$code=str_replace('\\>','>',$code);
var_export(json_decode($code));
But then, you know the domain of your data.
And you should apply a grain of salt before applying that blindly to all your inputs.
You could run stripslashes on it, and then pass that sring into json_decode.

escaping json string with a forward slash?

I am having a problem passing a json string back to a php script to process.
I have a json string that's been created by using dojo.toJson() that contains a / and looks like this:
[{"id":"2","company":"My Company / Corporation","jobrole":"Consultant","jobtitle":"System Integration Engineer"}]
When I pass the string back to the php script it get's chopped at the / and creates a malformed json string, which then means I can't convert it into a php array.
What is the best way of escaping the / in this string? I was looking at regular expressions and doing a string.replace() however my regex isn't that strong, and I'm not sure if there are better ways of doing this?
Many thanks
You shouldn't need to do anything special to represent a / in JSON - a string can contain any character except a " or (when not used to start an escape sequence) \.
The problem is possibly therefore in:
the way you parse the JSON server side
the way your parse the HTTP data to get the JSON string
the way you encode the string before making the HTTP request
(I'd bet on it being the last of those options).
I would start by using a tool such as LiveHttpHeaders or Charles Proxy to see exactly what data is sent to the server.
(I'd also expand the question with the code you use to make the request, and the code you use to parse it at the other end).
\/. Take a look here. The documentation is really easy to read, concise and clear. But unescaped / should still be valid in JSON's string so maybe your bug is somewhere else?
Ok. Anyway.
When passing variables to PHP don't use JSON - it's good for passing variables other way.
Instead you better use http://api.dojotoolkit.org/jsdoc/1.3/dojo.objectToQuery method and on PHP side parse standard PHP $_GET variables.
EDIT: Ok, I'm 'lost in the woods' here also, but here's a tip - check if you don't have some mod_rewrite rules in action here. Kind of seems like that.
Also, if you can send me the URL which gave you 404 (you can cut out domain part, i'm interested in script filename and all afterwards) maybe I can give you more detailed answer.
To be clear, whether you choose to send JSON to PHP or use regular form values is a matter of preference. It /should/ work either way. It sounds like you aren't url-encoding the JSON at the client-side so the server-side is treating / as a path delimiter. In which case its borked before json_decode gets to it.
so, try encodeURIComponent( dojo.toJson(stuff) )
json_encode() used to escape forward slashes. like this:
prompt> json_encode(json_decode('"A/B"'));
string(6) ""A\/B""
JSON_UNESCAPED_SLASHES was added in PHP5.4 to suppress this behavior.

Categories