• 0

c# Short URL from GUID


Question

Hello gang,

 

I am working on a new project for a site and I would like to implement short urls.  Historically I have used GUIDs as table ids so that replication is not an issue.  So, now I'm looking at creating a short url for these values, the thing is a shortened guid is not that short (vs a shortened Int) Before getting too far down a path, I thought I'd ask if anyone had any thoughts.

 

Thanks

Link to comment
https://www.neowin.net/forum/topic/1203663-c-short-url-from-guid/
Share on other sites

16 answers to this question

Recommended Posts

  • 0

Just generate strings of whatever size you consider to be short, made up of numbers, uppercase letters and lowercase letters, and associated them with your ID field.

 

[short_url_assoc_table]

table_id : GUID

short_url : string

  • 0
  On 06/03/2014 at 20:00, firey said:

What is it you are trying to do?

Like you have something say:

guasd3 = www.google.ca

-3idjqis = www.neowin.net

or?  

I guess I don't understand what you are trying to do exactly.

 

 

I need to use GUIDs as the table ident fields for the issue of replication.  If I use numeric values for the identity, which is easy to convert to a short URL by using Base64 (quite a number of examples around the net for doing this)  however if I use numeric I'm going to have collisions when multiple machines are making new records.  When I have looked at making a short url from a guid, the value is shorter than the GUID, but still longer than the average short GUID.

 

  On 06/03/2014 at 20:32, virtorio said:

Just generate strings of whatever size you consider to be short, made up of numbers, uppercase letters and lowercase letters, and associated them with your ID field.

 

[short_url_assoc_table]

table_id : GUID

short_url : string

 

Interesting idea, but this could be an issue with replication.  I am also concerned about multiple identity fields (waste of time, space, etc)   Thanks though

  • 0
  On 06/03/2014 at 21:16, James Rose said:

 

 

Interesting idea, but this could be an issue with replication.  I am also concerned about multiple identity fields (waste of time, space, etc)   Thanks though

 

What exactly is being replicated?

 

 

  On 06/03/2014 at 21:16, James Rose said:

I need to use GUIDs as the table ident fields for the issue of replication.  If I use numeric values for the identity, which is easy to convert to a short URL by using Base64 (quite a number of examples around the net for doing this)  however if I use numeric I'm going to have collisions when multiple machines are making new records.  When I have looked at making a short url from a guid, the value is shorter than the GUID, but still longer than the average short GUID.

What am I missing here? This shouldn't be an issue with a relational database. You don't tell your database what the ID of a row is, you let the database decide when it inserts the row(s).

  • 0

Im not sure where replication is happening.  Also why do you have to use guids for the identity, why not just use an incrementing number, and hash it's value or something to get the url you want to use?  Also, the database should be able to handle the ID itself.. and there should never be an issue of too many inserts causing problems.

  • Like 1
  • 0

Okay gang,

 

Replication of tables between multiple servers cannot use numeric values as, for example in SQL Server the Identity value is incrimented by 1 (and yes, you can change this value, but it wouldn't help when the app needs to scale)  Imagine two servers, each one adding new values to a table; "Customers" One each server they would both get identity #1 for the first record, when the two servers attempt to merge (ever hour, every minute, whenever) there would be a collision since there would be two records with the same identity value.  Using GUIDs for the key field avoids this issue as it is, almost, impossible to have the same guid twice.

 

 

Thanks Asik, however the "guidAsString" variable is still too long to be a short url.

  • 0

Looks like I found the answer.

                //Guid guid = Guid.NewGuid();
                string sGUID = "a33d4a21-7d95-41f7-859e-bf02b2fda650"
                string hashCode = String.Format("{0:X}", sGUID.GetHashCode());
                Console.WriteLine(hashCode);

This makes a nice small url, can anyone think of why this should not be used?

  • 0

^you shouldn't use it for the reasons listed here (about uniqueness guarantees and differences between versions): http://stackoverflow.com/questions/7458139/net-is-type-gethashcode-guaranteed-to-be-unique

 

Hash the GUID using SHA1 and truncate it or something like that. That's probably the best you are going to do. (perhaps you will have to truncate it to much, forcing a too high of probability for collision -- you should check the probability).

 

EDIT: Oh also, if you encode the result of hashing in a higher base, you reduce the amount of information loss during truncation.

  • 0
  On 06/03/2014 at 22:13, snaphat (Myles Landwehr) said:

^you shouldn't use it for the reasons listed here (about uniqueness guarantees and differences between versions): http://stackoverflow.com/questions/7458139/net-is-type-gethashcode-guaranteed-to-be-unique

 

Hash the GUID using SHA1 and truncate it or something like that. That's probably the best you are going to do. (perhaps you will have to truncate it to much, forcing a too high of probability for collision -- you should check the probability).

 

EDIT: Oh also, if you encode the result of hashing in a higher base, you reduce the amount of information loss during truncation.

 

EDIT:  Maybe what the article is saying, and what you are trying to tell me is that two different GUIDs could return the same hex?

 

 

 

Pardon me if I appear dense; I just read that article and ran some test against the same guid value for 1 billion iterations and it always comes up with the same hex.  I understand that 1 billion isn't necessarily that large a number...  what I am asking is shouldn't the hex value for a specific string always return the same hex value. 

 

Quote: "does not guarantee unique return values for different objects."  Since the app will pull the guid from the db, and then issue a hex on demand wouldn't that value always be the same?

 

Thanks for your input

  • 0
  On 06/03/2014 at 22:25, James Rose said:

Pardon me if I appear dense; I just read that article and ran some test against the same guid value for 1 billion iterations and it always comes up with the same hex.  I understand that 1 billion isn't necessarily that large a number...  what I am asking is shouldn't the hex value for a specific string always return the same hex value. 

 

Quote: "does not guarantee unique return values for different objects."  Since the app will pull the guid from the db, and then issue a hex on demand wouldn't that value always be the same?

 

Thanks for your input

 

It's the same each time because you are using the same version of the .net runtime on the same object for each run so it's producing the same hash. What they are saying is really two things: (1) if you switch versions of the .net runtime (e.g. 3.5 to 4), the returned result can be different for the same object, and (2) and within the same version of the runtime (e.g. 4) there can be collisions in hashes between different objects. There are no uniqueness guarantees.

 

So for example GUID_A.getHashCode() can return different results if you switch .net runtimes. And GUID_B.getHashCode() and GUID_C.getHashCode() could return the same result in the same runtime.

  • 0
  On 06/03/2014 at 22:31, snaphat (Myles Landwehr) said:

So for example GUID_A.getHashCode() can return different results if you switch .net runtimes. And GUID_B.getHashCode() and GUID_C.getHashCode() could return the same result in the same runtime.

 

yea, this is the answer I finally got to (see my edit above).  I was having a very hard time getting to the idea that a 30+ char piece of data could reliably be set to a shorter value.

  • 0
  On 06/03/2014 at 22:39, James Rose said:

yea, this is the answer I finally got to (see my edit above).  I was having a very hard time getting to the idea that a 30+ char piece of data could reliably be set to a shorter value.

Well in any case, you should re-encode whatever you do use to a higher number base that is still valid as url characters. For example, as I was saying before if you do the following you can store more information of your hash in less characters. 

String result=re_encode_as_base_X(SHA1_hash(GUID), N) //base 16 --> base N

I think at the end of the day, you will have to truncate though regardless of what you do. 

  • 0

It turns out I may be suffering from "doing this too long" desease.  Someone was kind enough to send a private message to me that the issue of replication on numeric  idenities may no longer be the issue it used to be.

 

I'm reading this article now:  http://technet.microsoft.com/en-us/library/ms146907%28v=sql.105%29.aspx

  • Like 1
  • 0
  On 06/03/2014 at 22:01, James Rose said:

Thanks Asik, however the "guidAsString" variable is still too long to be a short url.

I was suggesting taking the BigInteger and passing it through whatever method you mentionned that converted numerical values into short URLs, not taking it as a string directly. Anyway, looks like you found your answer.

This topic is now closed to further replies.
  • Posts

    • Ea and Ubisoft's already have a 3rd party client mode where it removes the store features from the client and only uses 60mb of ram rather than 700.... I use playnite for gog and epic games because the the third party legendary client etc Combined in playnite epic and gog only use 200mb/ram while also showing my entire library from every other platform...
    • Also, this domain thing only works with Pro version of Windows, not the home version
    • More useless bloat to kill your pc by accident
    • Windows 11 gets more customization, a Recall home page, and more in new builds by Taras Buria Microsoft kicks off this Monday with a duo of nearly identical builds for Windows Insiders in the Dev and Beta Channels. Build 26200.5661 (Dev) and 26120.4452 (Beta) are now available for download with two big changes: a new home page for Recall and the recently spotted ability to customize where system indicators appear on the screen. The new Recall home page features more personalized content to help you get back to recent activities. It displays your latest snapshots and a curated view of the top three applications and websites you have spent the most time on in the past 24 hours. Here is what it looks like: In addition, Recall received a new nav bar on the left side of the screen with quick links to Home, Timeline, Feedback, and Settings. The next big addition is the ability to change where system indicators (brightness, volume, and more) appear on the screen. Now, you can set these at the top-left corner or top-center. To adjust this, go to Settings > System > Notifications > Position of the onscreen pop-up. Here are other changes included in today's builds: [Start menu] We are adding a Boolean to the Configure Start Pins policy to allow admins to apply Start menu pins once. This means that a user will receive admin pins on day 0 but can then make any changes to their Start pinned layout and have those safeguarded. These changes can be optionally applied through the existing configuration service provider (CSP). [File Explorer] We are restarting the roll out of AI actions in File Explorer that began rolling out with Build 26120.4151. Some Insiders may have seen the feature disappear. [Settings] In the most recently flights, we have added the country or region selected during device setup under Settings > Time & language > Language & region. Here is what was fixed: [General] Fixed the issue causing the Windows Vista boot sound to play instead of the Windows 11 boot sound. Fixed an issue where the option to reset your PC under Settings > System > Recovery wasn’t working on the previous build. Fixed an underlying issue leading to certain KVM virtual machines unexpectedly failing to boot, showing “UNSUPPORTED_PROCESSOR”. The Dev build has an extra fix: Fixed the issue causing a small number of Insiders to experience repeated bugchecks with KERNEL_SECURITY_CHECK_FAILURE after upgrading to most current Dev Channel builds. Known issues include the following: [General] [IMPORTANT NOTE] When joining the Beta Channel on Windows 11, version 24H2 – you will be offered Build 26120.4250 After installing Build 26120.4250, you will be offered the most recent update available. This 2-hop experience to get onto the latest flight in the Beta Channel is just temporary. After you do a PC reset under Settings > System > Recovery, your build version may incorrectly show as Build 26100 instead of Build 26120. This will not prevent you from getting future Beta Channel updates, which will resolve this issue. Some Windows Insiders may experience a rollback trying to install this update with a 0x80070005 in Windows Update. We’re working on a fix for Windows Insiders impacted. [Start menu] The following are known issues for Windows Insiders with the new Start menu: Using touch to navigate the new Start menu may not work reliably. For example, it currently does not support the swipe-up gesture. Drag and drop capabilities are limited from “All” to “Pinned.” In some cases, duplicate entries may appear in folders on the Start menu. [Xbox Controllers] Some Insiders are experiencing an issue where using their Xbox Controller via Bluetooth is causing their PC to bugcheck. Here is how to resolve the issue. Open Device Manager by searching for it via the search box on your taskbar. Once Device Manager is open, click on “View” and then “Devices by Driver”. Find the driver named “oemXXX.inf (XboxGameControllerDriver.inf)” where the “XXX” will be a specific number on your PC. Right-click on that driver and click “Uninstall”. [Click to Do (Preview)] The following known issues will be fixed in future updates to Windows Insiders: Windows Insiders on AMD or Intel™-powered Copilot+ PCs may experience long wait times on the first attempt to perform intelligent text actions in Click to Do after a new build or model update. [File Explorer] The following are known issues for AI actions in File Explorer: Narrator scan mode may not work properly in the action result canvas window for the Summarize AI action for Microsoft 365 files when reading bulleted lists. As a workaround, you can use Caps + Right key to navigate. [Widgets] Until we complete support for pinning in the new widgets board experience, pinning reverts you back to the previous experience You can find the announcement for the Dev build here and for the Beta build here.
    • Doesn't that assume that there is only one potential use-case scenario when in fact there are millions of people who live in urban areas that only require a small fraction of that?
  • Recent Achievements

    • One Month Later
      adnan.hebibovic earned a badge
      One Month Later
    • Week One Done
      adnan.hebibovic earned a badge
      Week One Done
    • Dedicated
      tesla maxwell earned a badge
      Dedicated
    • Dedicated
      Camlann earned a badge
      Dedicated
    • Week One Done
      fredss earned a badge
      Week One Done
  • Popular Contributors

    1. 1
      +primortal
      629
    2. 2
      Michael Scrip
      224
    3. 3
      ATLien_0
      220
    4. 4
      +FloatingFatMan
      144
    5. 5
      Xenon
      134
  • Tell a friend

    Love Neowin? Tell a friend!