IIS Url Rewite: Add Trailing Slash, Preserve Anchors and Query Strings - Nginx

RoLYroLLs
January 11, 2022
144 views
0 votes
2 Answers

I’ve searched several SO posts and haven’t found what I’m looking for. It might exists but might be fairly old enough to not show up for me. I found a post (Nginx rewrite: add trailing slash, preserve anchors and query strings) so close to what I need, but it’s regex solution does not work for URL Rewrite for IIS, unless I’m doing it wrong.

Problem

I’m trying to add a forward slash / to the end of my url paths while also preserving any existing for query strings ? and anchors #.

Desired Solution

Basically, here’s the desired results to each problem:

Entry: https://my.site.com/about
Result: https://my.site.com/about/

Entry: https://my.site.com/about?query=string
Result: https://my.site.com/about/?query=string

Entry: https://my.site.com/about#TestAnchor
Result: https://my.site.com/about/#TestAnchor

Entry: https://my.site.com/about?query=string#TestAnchor
Result: https://my.site.com/about/?query=string#TestAnchor

Current Tests

Our current regex ignores query strings and anchors, but I would like to take them into consideration now.

<rule name="AddTrailingSlash" stopProcessing="true">
  <match url="^([^.?]+[^.?/])$" />
  <action type="Redirect" url="{R:1}/" redirectType="Permanent" />
</rule>

I’ve also tested another regex but it only works if the url contains both a query string AND an anchor.

<rule name="AddTrailingSlash" stopProcessing="true">
  <match url="^(.*)(?.*?)(#.*?)$" />
  <action type="Redirect" url="{R:1}/{R:2}{R:3}" redirectType="Permanent" />
</rule>

NOTE: I just tested this last one (^(.*)(?.*?)(#.*?)$) and it actually doesn’t work. If the url already contains a / before the ? the test passes which it should not, so I have more work to do here.

Question

Is there a single regex that I can use to solve this or do I need to use multiple rules?

Answers

- K225rolySzab243
- February 1, 2022 at 10:11 am
- 0 votes
0
You can try with this regex https://regex101.com/r/6TSqaP/2. This is matching every provided example and solves the problem if the url already has an ending '/'.
```
^((?:https?://[w.-]*)(?:[w-]+/)*(?:[w-]+)(?!/))(?.*?)?(#.*?)?$
```
I used your second example as base for my regex, with the following logic.
The parts of the url: scheme://authority/path?query#fragment
1. first capture group matches the scheme://authority/path part of the url
2. second capture group optional and matching the ?query
3. third capture group also optional and for the #fragment
regex explanation
```
^(                            # should start with this
    (?:https?://[w.-]*)  # match the http or https protocol and the domain
    (?:[w-]+/)*            # match the path except the last element of it (optional)
    (?:[w-]+)(?!/)         # match the last path element, but only if it's not closed with '/'
)                             # {R:1}
(?.*?)?                      # {R:2} query (optional)
(#.*?)?                      # {R:3} fragment (optional)
$                             # string should end
```
Nginx
```
<rule name="AddTrailingSlash" stopProcessing="true">
  <match url="^((?:https?://[w.-]*)(?:[w-]+/)*(?:[w-]+)(?!/))(?.*?)?(#.*?)?$" />
  <action type="Redirect" url="{R:1}/{R:2}{R:3}" redirectType="Permanent" />
</rule>
```
Edit: Updated regex to handle dashes (-) and multiple path elements
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TL;DR

IIS Rewrite (ALL) URIs with `Trailing Slash` & preserve `Fragment` and `Query Strings`

<rule name="AddTrailingSlash" stopProcessing="true">
  <match url="^([^/]+://[^/#?]+|[^?#]+?)/?((?:[^/?#]+.[^/?#]+)?(?:[?#].*)?$)" />
  <action type="Redirect" url="{R:1}/{R:2}" redirectType="Permanent" />
</rule>

IIS use ECMAScript so you can Try it here : https://regexr.com/6ele7

Update

IIS Rewrite (Considered) URIs with `Trailing Slash` & preserve `Fragment` and `Query Strings`

<rule name="AddTrailingSlash" stopProcessing="true">
  <match url="^([^/]+://[^/#?]+|[^?#]+/[^/.?#]+)([?#].*)?$" />
  <action type="Redirect" url="{R:1}/{R:2}" redirectType="Permanent" />
</rule>

Try it here : https://regexr.com/6fk3g

http://127.0.0.1  -->  http://127.0.0.1/
https://localhost  -->  https://localhost/
https://localhost?  -->  https://localhost/?
https://localhost/  -->  https://localhost/
https://my.site.com  -->  https://my.site.com/
https://my.site.com:443?  -->  https://my.site.com:443/?
https://my.site.com/  -->  https://my.site.com/
https://my.site.com/about.php  -->  https://my.site.com/about.php
https://my.site.com/about.php?  -->  https://my.site.com/about.php?
https://my.site.com/about  -->  https://my.site.com/about/
https://my.site.com/about?  -->  https://my.site.com/about/?
https://my.site.com/about/  -->  https://my.site.com/about/
https://my.site.com/about/?  -->  https://my.site.com/about/?
https://my.site.com/about?query  -->  https://my.site.com/about/?query
https://my.site.com/about/?query  -->  https://my.site.com/about/?query
https://my.site.com/about.php?query  -->  https://my.site.com/about.php?query
https://my.site.com/about#hash  -->  https://my.site.com/about/#hash
https://my.site.com/about/#hash  -->  https://my.site.com/about/#hash
https://my.site.com/about.php#hash  -->  https://my.site.com/about.php#hash
https://my.site.com/about?query#hash  -->  https://my.site.com/about/?query#hash
https://my.site.com/about/?query#hash  -->  https://my.site.com/about/?query#hash
https://my.site.com/folder.name/about?query  -->  https://my.site.com/folder.name/about/?query
https://my.site.com/about?query#hash:http://test.com?q  -->  https://my.site.com/about/?query#hash:http://test.com?q

Explaination (All)

Level 1 – Lets just think about your examples:

^([^?#]+?)/?([?#].*)?$

Group #1: ^ In first, [^?#] Any character except ?/#, Go much but lazy +? (Stop on first possible, by looking to next)
Ignore: /? Then if a / exist or not
Group #2: [?#] = ?/# And .* Any much character next to that till $ End, (...)? If exist

It work well. But it will deal not right with:

https://my.site.com/about.php?query  -->  https://my.site.com/about.php/?query  !!!

So let’s add an exception…

Level 2 – How if we take possible file name Name.name.name.ext as Group #2?

^([^?#]+?)/?((?:[^/?#]+.[^/?#]+)?(?:[?#].*)?)$

(?:...) Non-Capturing group
([^/?#]+.[^/?#]+)? Look for any possible file name or (?:[?#].*)? Any possible query or anchor strings

Now everything is OK, except this:

https://my.site.com?  -->  https://my.site.com?  !!!

So we need another exception in Group #1

Level 3 – Take just domain URI as an alternative

^([^/]+://[^/#?]+|[^?#]+?)/?((?:[^/?#]+.[^/?#]+)?(?:[?#].*)?$)

(...|...) Alternative
[^/]+://[^/#?]+ First check if (not lazy) any pattern like ...://... till not / # ? exist?

Now it work great!

+ Explaination (Considered)

Level 4 – How if we just add a Not-Accepting . & / character set in first group to just match considered URIs and ignore others?

^([^/]+://[^/#?]+|[^?#]+/[^/.?#]+)([?#].*)?$

/[^/.?#]+ Check if after last / the set of characters be not /.?#

Now it is even smaller and faster!

Analyzing other method

As @károly-szabó answered well here, instead of looking for Not-Accepted character sets, we can look for matched pattern.
So if we want to use the method but in simpler way (2 Groups) (+ Some minor optimization), the regex will be:

^(https?://[w.:-]+/?(?:[w.-]+/)*[w-]+(?!/))([?#].*)?$

But URI path Accepted characters are more.

So a wider version of that Regex can be:

^(https?://[w.:-]+/?(?:[w!#-)+-.;=@~]+/)*[w!#-);=@~+,-]+(?!/))([?#].*)?$

Try it here: https://regexr.com/6elea

Note: Still "multibyte Unicode as domain name is allowed" but i ignored that in this method.

P.S.

Actually i don’t think that we should rewrite it on IIS, because of these reasons:

Anchors char # can be part of a folder name (by %23)
A file name can have no extension
IIS/Browsers usually will (/should) handle Anchors/Queries
Ref:

I Mean:

https://my.site.com/  -->  (=Call root)
https://my.site.com/about  -->  (=Call root > Folder/File name about) 
https://my.site.com/about/  -->  (=Call root > Folder name about) 
https://my.site.com/about?query  -->  (=Call root > Folder/File name about + Query)
https://my.site.com/about/?query  -->  (=Call root > Folder name about + Query)
https://my.site.com/about.php?query  -->  (=Call root > File name about.php + Query)
[When browser strip it:]
https://my.site.com/about#hash  -->  (=Call root > Folder/File name about + Anchor)
https://my.site.com/about/#hash  -->  (=Call root > Folder name about + Anchor)
https://my.site.com/about.php#hash  -->  (=Call root > File name about.php + Anchor)

[If not?]
https://my.site.com/folder#name/?query#hash
https://my.site.com/folder.name/about.php?query=one/two

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IIS Url Rewite: Add Trailing Slash, Preserve Anchors and Query Strings – Nginx