Today I want to introduce something I’ve been working on recently which could be of use to you if you’re a SharePoint developer. Often when developing SharePoint solutions which require coding, the developer faces a decision about what to do with values he/she doesn’t want to ‘hardcode’ into the C# or VB.Net code. Example values for a SharePoint site/application/control could be:
‘AdministratorEmail’ – ‘email@example.com’
‘SendWorkflowEmails’ – ‘true’
Generally we avoid hardcoding such values, since if the value needs to be changed we have to recompile the code, test and redeploy. So, alternatives to hardcoding which folks might consider could be:
- store values in appSettings section of web.config
- store values in different places, e.g. Feature properties, event handler registration data, etc.
- store values in a custom SQL table
- store values in a SharePoint list
Personally, although I like the facility to store complex custom config sections in web.config, I’m not a big fan of appSettings. If I need to change a value, I have to connect to the server using Remote Desktop and open and modify the file – if I’m in a server farm with multiple front-ends, I need to repeat this for each, and I’m also causing the next request to be slow because the app domain will unload to refresh the config. Going through the other options, the second isn’t great because we’d need to be reactivating Features/event receiver registrations every time (even more hassle), though the third (using SQL) is probably fine, unless I want a front-end to make modifying the values easier, in which case we’d have some work to do.
So storing config values in a SharePoint list could be nice, and is the basis for my solution. Now I’d bet lots of people are doing this already – it’s pretty quick to write some simple code to fetch the value, and this means we avoid the hardcoding problem. However, the Config Store ‘framework’ goes further than this – for one thing it’s highly-optimized so you can be sure there is no negative performance impact, but there are also some bonuses in terms of where it can used from and the ease of deployment. So what I hope to show is that the Config Store takes things quite a bit further than just a simple implementation of ‘retrieving config values from a list’.
Details (reproduced from the Codeplex site)
The list used to store config items looks like this (N.B. the items shown are my examples, you’d add your own):
There is a special content type associated with the list, so adding a new item is easy:
..and the content type is defined so that all the required fields are mandatory:
Once a value has been added to the Config Store, it can be retrieved in code as follows (you’ll also need to add a reference to the Config Store assembly and ‘using’ statement of course):
string sAdminEmail = ConfigStore.GetValue("MyApplication", "AdminEmail");
Note that there is also a method to retrieve multiple values with a single query. This avoids the need to perform multiple queries, so should be used for performance reasons if your control/page will retrieve many items from the Config Store – think of it as a best practise. The code is slightly more involved, but should make sense when you think it through. We create a generic List of ‘ConfigIdentifiers’ (a ConfigIdentifier specifies the category and name of the item e.g. ‘MyApplication’, ‘AdminEmail’) and pass it to the ‘GetMultipleItems()’ method:
List<ConfigIdentifier> configIds = new List<ConfigIdentifier>();
ConfigIdentifier adminEmail = new ConfigIdentifier("MyApplication", "AdminEmail");
ConfigIdentifier sendMails = new ConfigIdentifier("MyApplication", "SendWorkflowEmails");
Dictionary<ConfigIdentifier, string> configItems = ConfigStore.GetMultipleValues(configIds);
string sAdminEmail = configItems[adminEmail];
string sSendMails = configItems[sendMails];
..the method returns a generic Dictionary containing the values, and we retrieve each one by passing the respective ConfigIdentifier we created earlier to the indexer.
- All items are wrapped up in a Solution/Feature so there is no need to manually create site columns/content types/the Config Store list etc. There is also an install script for you to easily install the Solution.
- Config items are cached in memory, so where possible there won’t even be a database lookup!
- The Config Store is also designed to operate where no SPContext is present e.g. a list event receiver. In this scenario, it will look for values in your SharePoint web application’s web.config file to establish the URL for the site containing the Config Store (N.B. these web.config keys get automatically added when the Config Store is installed to your site). This also means it can be used outside your SharePoint application, e.g. a console app.
- The Config Store can be moved from it’s default location of the root web for your site. For example sites I create usually have a hidden ‘config’ web, so I put the Config Store in here, along with other items. (To do this, create a new list (in whatever child web you want) from the ‘Configuration Store list’ template (added during the install), and modify the ‘ConfigWebName’/’ConfigListName’ keys which were added to your web.config to point to the new location. As an alternative if you already added 100 items which you don’t want to recreate, you could use my other tool, the SharePoint Content Deployment Wizard at http://www.codeplex.com/SPDeploymentWizard to move the list.)
- All source code and Solution/Feature files are included, so if you want to change anything, you can
- Installation instructions are in the readme.txt in the download
Hopefully you might agree that the Config Store goes beyond a simple implementation of ‘storing config values in a list’. For me, the key aspects are the caching and the fact that the entire solution is ‘joined up’, so it’s easy to deploy quickly and reliably as a piece of functionality. Many organizations are probably at the stage where their SharePoint codebase is becoming mature and perhaps based on a foundation of a ‘core API’ – the Config Store could provide a useful piece in such a toolbox.
You can download the Config Store framework and all the source code from www.codeplex.com/SPConfigStore.