negibokken / github-url-test

The research about GitHub permalink rule.

GitHub permanlink test

This repository is for checking the rule of generating GitHub permalink.

For example the permalink for a file like below

/@foo/[bar]/a !"#$%&'()*+,-.:;<=>?@[\\]^`{|}~.txt

is

/@foo/%5Bbar%5D/a%20!%22%23$%25&'()\*+,-.:;%3C=%3E%3F@%5B%5C%5D%5E%60%7B%7C%7D~.txt

The basic

The GitHub URL consists of like following parts https://github.com/${owner}/${repository}/blob/${commit_hash}/${path_to_file}?query=parameter#fragment.

The ${commit_hash} is simple, but ${owner}, ${repository}, and ${path_to_file} can contain symbols like !"#$%&'()\*+,-.:;<=>?@[\\]^\{|}~`.

Then the permalink has encoded strings. This repository is for the research.

The Rule for generating permalink

The encode rule is summarized in the below table.

Symbol	GitHub permalink	encodeURI	encodeURIComponent
SP	%20	%20	%20
!	!	!	!
"	%22	%22	%22
#	%23	#	%23
$	$	$	%24
%	%25	%25	%25
&	&	&	%26
'	'	'	'
(	(	(	(
)	)	)	)
*	*	*	*
+	+	+	%2B
,	,	,	%2C
-	-	-	-
.	.	.	.
/	/	/	/
:	:	:	%3A
;	;	;	%3B
<	%3C	%3C	%3C
=	=	=	%3D
>	%3E	%3E	%3E
?	%3F	?	%3F
@	@	@	%40
[	%5B	%5B	%5B
\	%5C	%5C	%5C
]	%5D	%5D	%5D
^	%5E	%5E	%5E
`	%60	%60	%60
{	%7B	%7B	%7B
|	%7C	%7C	%7C
}	%7D	%7D	%7D
~	~	~	~

The result of permalink is almost same with the result of encodeURI except for # and ?.

I think the reason why # and ? are encoded is # and ? have a special meaning for the URL. (i.e. # is for fragment, ? is query parameter.)

Conclusion

To generate the permalink for a file that includes symbols, follow the below steps.

1. Split the url into from scheme to path as BASE, and query and fragment part as ADDITIONAL
   • i.e. https://example.com/@foo/[bar]/baz#?!&$.txt and ?query=test#some-fragment
2. Run encodeURI to BASE and replace # into %23 and ? into %3F
3. Concatenate BASE and ADDITIONAL
   • https://example.com/@foo/%5Bbar%5D/baz%23?!&$.txt?query=test#some-fragment