ShortUrl

Short url redirector with no database required. DotNet Core 3.1 and Net 5/6 version.

Language: C#

Platform: ASP.Net Core 3.1, Net 5/6

Features

• No database required.
• Multiple host names supported.

Installation

• Linux with systemd and nginx.
• Windows with IIS.

Management

• Management
• Edit the configuration file directly when HTTPS is not available.

Known Issue

• Due to lack of support of http code 308 in IE on Windows 7 / 8.1, do NOT check "Use HTTP 308" / "Use HTTP 308 instead of 307" if you need to support old IE versions.

Work flow

When a request is received by ShortUrl, it will follow these steps.

1. Gets the host from the HTTP Header.
   • When preferXForwardedHost in configuration file is set to true and X-Forwarded-Host exists in HTTP Header, gets the host from X-Forwarded-Host.
   • Gets the host from Host in HTTP Header.
2. Gets the path segments from the HTTP Header as the access key.
3. Enters the Global Management page when
   • The access key equals to Global Management Key. And,
   • The host is allowed to enter Global Management page when
     • The host exists(*1) in Global Management Enabled Hosts. Or,
     • The list Global Management Enabled Hosts is empty.
4. Resolves by aliases when the host equals(*1) the Alias column of one record in Aliases from Global Management, choosing Target as the new value of host and restart this step. Aliases could be resolved recursively with 16 as the max depth.
5. Processes the request against the domain when the host equals(*1) Domain column of one record in Domains from Global Management.
   1. Enters the Domain Management page when access key equals to Domain Management Key.
   2. Resolves by redirects when the access key equals(*2) the address column of one record in Redirects from Domain Management of this domain.
      • When the Target from the record matched is starting with >, gets the text after > from Target as the new value of access key and restart this step. Redirects could be resolved recursively with 16 as the max depth. Or,
      • Redirects to Target specified of the record matched.
   3. Redirects to Default Redirect Target specified in Domain Management of this domain if it is not empty.
6. Redirects to Default Redirect Target specified in Global Management.

*1: Host name matching rules:

• Host name matching is case insensitive.
• Port number 80 or 443 should not present, but all others should and will be treated separately. For example:
  • The record "example.com" will be matched with the host "example.com", "example.com:80" and "example.com:443".
  • The record "example.com:8080" will be matched with the host "example.com:8080" only.
• The record with the key ends with ":80" or ":443" in domains or aliases will not be matched unless it's pointed by other matched alias records.

*2: Name matching could be case sensitive or insensitive, based on the setting Ignore Case When Matching specified in the Domain Management of the related domain.

When redirecting:

• HTTP 308 will be used, when Use HTTP 308 instead of 307 or Use HTTP 308 is selected. Or HTTP 307 will be used.
• When Attach Query Process is enabled and the query string exists from the request:
  • When character ? presents in the target of the redirection, & and the query string from the request will be appended.
  • When character ? absents from the target of the redirection, ? and the query string from the request will be appended.
• When Attach Query Process is disabled, the query string, if exists, from the request will be dropped and will not be passed into the redirection target.