percent encoding - how is a greek letter percent encoded? - character-encoding

I'm browsing the web for a answer but cannot find one. I have a HTML form (method=GET) and submit in a text field the text helloΩ (hello with the greek letter Omega appended)
The URL in the browser encodes it as:
mytext=hello%26%23937%3B
Without the greek letter Omega appended, I get (as expected):
mytext=hello
So how is the greek Omega letter percent encoded into:
%26%23937%3B
Thanks

This happens when your web server declared an encoding that doesn't support the character. For example, ISO-8859-1 doesn't support it which is the default encoding for many web servers.
That's a html entity character reference percent-encoded: Ω, because #, & .. are all ASCII characters, this is the only way to not lose information because the browser thinks the server only supports ISO-8859-1.
To fix this, declare UTF-8 in your http header:
Content-Type: text/html; charset=utf-8
This isn't even consistent behavior between browsers, because IE encodes it as hello%D9, which is Ú in CP1252/ISO-8859-1.

Related

Issue with html decoding in Delphi

I have a problem with TNETEncoding.HTML.Decode in Delphi 10.3.3 (rio).
It seems the decoding is not functioning correctly but maybe i'm doing something wrong here.
var s := TNETEncoding.HTML.Decode('carrière');
returns in s:
'carrière'
It should be 'carrière' (without de quotes). See: https://www.convertstring.com/en/EncodeDecode/HtmlDecode
Is there something i'm doing wrong here?
According to the official documentation of THTMLEncoding, it only supports character entities for the reserved HTML characters ", &, <, and >:
THTMLEncoding only encodes reserved HTML characters: "&<>.
But it also is able to decode numeric character references:
THTMLEncoding supports decoding any HTML numeric character reference, such as © or þ, as well as the character entity references of reserved HTML characters: ", &, <, >.
So the only named character entities it supports are the ones for the HTML reserved characters ", &, <, and >.
Indeed, the documentation emphasises and warns
Warning: Decoding character entity references of non-reserved characters, such as &apos; or ©, is not supported. The input data must not contain any other character entity references. Otherwise, the output data may be corrupted.
Fortunately, this SO question (and the answer by Ian Boyd) contains code to decode HTML character entities other than those for the reserved characters.

What scheme is used to encode unicode characters in a .url shortcut?

What scheme is used to encode unicode characters in a windows url shortcut?
For example, a new shortcut for url "http://Ψαℕ℧▶" produces a .url file with the text:
[{000214A0-0000-0000-C000-000000000046}]
Prop3=19,2
[InternetShortcut]
IDList=
URL=http://?aN??/
[InternetShortcut.A]
URL=http://?aN??/
[InternetShortcut.W]
URL=http://+A6gDsSEVIScltg-/
What is the algorithm to decode "+A6gDsSEVIScltg-" to "Ψαℕ℧▶"?
I am not asking for API code, but I would like to know the encoding scheme details.
Note: The encoding scheme is not utf-8 nor utf-16 nor ucs-2 and no %encoding.
+A6gDsSEVIScltg- is the UTF-7 encoded form of Ψαℕ℧▶.
The correct way to process a .url file is to use the IUniformResourceLocator and IPropertyStorage interfaces from the CLSID_InternetShortcut COM object. See Internet Shortcuts on MSDN for details.
The answer (utf-7) allowed me to successfully develop the url conversion routine.
Let me summarize the steps:
To obtain the unicode url from a InternetShortcut.W found in a .url file.
. Pass ascii chars until crlf, after making them internet safe.
. A none escaped + character starts a utf-7 formatted unicode sequence:
. Collect 6-bit nibbles from base64 coded ascii
. Per collected 16 bits, convert the 16 bits to utf-8 (1,2, or 3 chars)
. Pass the utf8 generated characters as %hh
. Continue until the occurrence of a "-" character
. The bit collector should be zero

Where should my brackets be in relation to the text for Arabic languages?

Our application automatically modifies the layout of Arabic text when it is followed by a bracket and I was wondering whether this was the correct behaviour or not?
The application shows items in the following format:
[ID of structure](version)
So version 1.5 of the English structure "stackoverflow" would be displayed as:
stackoverflow(1.5)
Note: the brackets need to be displayed. There is no space between the ID and the first bracket. The brackets simply encompass the version. The brackets could have been any character but it's far too late to switch to a different character now!
This works fine for left to right languages, but for Arabic languages the structures appear in the form:
ستاكوفيرفلوو(1.0)
I am not an Arabic speaker and I need to know if this is actually correct. Is the Arabic format the equivalent of the English format or has something gone horribly wrong?
The text in Arabic should be shown like:
ستاكوفيرفلوو(1.0) ‏
I added the html entity of RLM / Right-to-left Mark ‏ in order to fix the text. You should do so if your application doesn't support Bidi native-ly. You can add the RLM by these ways:
HTML Entity (decimal) ‏
HTML Entity (hex) ‏
HTML Entity (named) ‏
How to type in Microsoft Windows Alt +200F
UTF-8 (hex) 0xE2 0x80 0x8F (e2808f)
UTF-8 (binary) 11100010:10000000:10001111
UTF-16 (hex) 0x200F (200f)
UTF-16 (decimal) 8,207
UTF-32 (hex) 0x0000200F (200f)
UTF-32 (decimal) 8,207
C/C++/Java source code "\u200F"
Python source code u"\u200F"
(note: StackOverflow right transliteration is ستاك-أوفرفلو)

Mime encoded headers with extra '=' (==?utf-8?b?base64string?=)

This might be a silly question but... here it goes!
I wrote my own MIME parser in native C++. It's a nightmare with the encodings! It was stable for the last 3 months or so but recently I noticed this Subject: header.
Subject: =?UTF-8?B?T2ZpY2luYSBkZSBJbmZvcm1hY2nDs24sIEluaWNpYXRpdmFzIHkgUmVjbGFt?===?UTF-8?B?YWNpb25lcw==?=
which should decode to this:
Subject: Oficina de Información, Iniciativas y Reclamaciones
The problem is there is one extra = (equal) in there which I can't figure out binding the two (why 2?) encoded elements which I don't understand why are separated. In theory the format should be: =?charset?encoding?encoded_string?= but found another subject that starts with two =.
==?UTF-8?B?blahblahlblah?=
How should I handle the extra =?
I could replace ==? with =? (which I am) before doing anything (and it works)... but I'm wondering if there's any kind of spec regarding this so I don't hack my way into proper functionality.
PS: How much I hate these relic protocols! All text communications should be UTF-8 and XML :)
In MIME headers encoded words are used (RFC 2047 Section 2.).
... (why 2?)
To overcome 75 encoded word limit, which is there because of 78 line length limit (or to use 2 different encodings like Chinese and Polish for example).
RFC 2047:
An 'encoded-word' may not be more than 75 characters long,
including 'charset', 'encoding', 'encoded-text', and delimiters.
If it is desirable to encode more text than will fit in an
'encoded-word' of 75 characters, multiple 'encoded-word's
(separated by CRLF SPACE) may be used.
Here's the example from RFC2047 (note there is no '=' in between):
Subject: =?ISO-8859-1?B?SWYgeW91IGNhbiByZWFkIHRoaXMgeW8=?=
=?ISO-8859-2?B?dSB1bmRlcnN0YW5kIHRoZSBleGFtcGxlLg==?=
Your subject should be decoded as:
"Oficina de Información, Iniciativas y Reclam=aciones"
mraq answer is incorrect. Soft line breaks apply to 'Quoted Printable' Content-Transfer-Encoding only, which can be used in MIME body.
It is called the "Soft Line Break" and it is the heritage of the SMTP protocol.
Quoting page 20 of RFC2045
(Soft Line Breaks) The Quoted-Printable encoding
REQUIRES that encoded lines be no more than 76
characters long. If longer lines are to be encoded
with the Quoted-Printable encoding, "soft" line breaks
must be used. An equal sign as the last character on a
encoded line indicates such a non-significant ("soft")
line break in the encoded text.
And also Wikipedia on Quoted-printable
A soft line break consists of an "=" at the end of an encoded line,
and does not appear as a line break in the decoded text.
From what I can see in the MIME RFC double equal signs are not valid input (for encoding), but keep in mind you could interpret the first equal sign as what it is and then use the following stuff for decoding. But seriously, those extra equal signs look like artifacts, maybe from an incorrect encoder.

What encoding type of these text?

When I search in Google by Thai language. Google will convert like these.
%E0%B8%A0%E0%B8%B2%E0%B8%A9%E0%B8%B2%E0%B9%84%E0%B8%97%E0%B8%A2
URL Encoding: See http://www.w3schools.com/tags/ref_urlencode.asp
It's a URL encoding in which all
non-alphanumeric characters except
-_. are replaced with a percent (%)
sign followed by two hex digits and
spaces encoded as plus (+) signs. It
is encoded the same way that the
posted data from a WWW form is
encoded, that is the same way as in
application/x-www-form-urlencoded
media type.
(Information copied from http://php.net/manual/en/function.urlencode.php)
UTF-8 + URL Encoding.

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