How to read sc.variable programmatically

Question

I have added a new sc.variable (just like dataFolder, tempFolder). We see the setting in showconfig.aspx but it returns an empty string when getting it with Sitecore.Configuration.Settings.GetSetting("mySetting").

I tried playing around with lowercase/uppercase as Sitecore.Configuration.Settings.GetSetting("dataFolder") returns empty but Sitecore.Configuration.Settings.GetSetting("DataFolder") returns the actual value; but didn't work either. Is it not possible to read custom sc.variable settings?

UPDATE: We are using sc.variable so we can read this setting from other .config files e.g. <bla value="$(mySetting)xxx /> but we also happen to need to read it programmatically.

Answer 1

All the variables from sc.variable are defined in two places For example tempFolder is defined :

 <sc.variable name="tempFolder" value="/temp" />

and

 <setting name="TempFolder" value="$(tempFolder)" /> 

The value of the TempFolder you can get using :

return Settings.GetSetting("TempFolder", "/temp") where the second parameter is default value.

So I recommend to declare your variable not like a sc.variable, but like normal setting. Or if you declare like a sc.variable declare a setting with a variable parameter.

Update: How sitecore replace this variables : On Sitecore.Configuration.ConfigReader it has a method:

protected virtual void ReplaceGlobalVariables(System.Xml.XmlNode rootNode)
{
    Assert.ArgumentNotNull(rootNode, "rootNode");
    System.Xml.XmlNodeList xmlNodeList = rootNode.SelectNodes(".//sc.variable");
    StringDictionary stringDictionary = new StringDictionary();
    foreach (System.Xml.XmlAttribute xmlAttribute in rootNode.Attributes)
    {
        string name = xmlAttribute.Name;
        string @string = StringUtil.GetString(new string[]
        {
            xmlAttribute.Value
        });
        if (name.Length > 0)
        {
            string key = "$(" + name + ")";
            stringDictionary[key] = @string;
        }
    }
    for (int i = 0; i < xmlNodeList.Count; i++)
    {
        string attribute = XmlUtil.GetAttribute("name", xmlNodeList[i]);
        string attribute2 = XmlUtil.GetAttribute("value", xmlNodeList[i]);
        if (attribute.Length > 0)
        {
            string key2 = "$(" + attribute + ")";
            stringDictionary[key2] = attribute2;
        }
    }
    if (stringDictionary.Count == 0)
    {
        return;
    }
    this.ReplaceGlobalVariables(rootNode, stringDictionary);
}

Answer 2

While the answer given by Sitecore Climber is spot on, I'd like to clarify a bit on the difference between sc.variable and a setting.

If you look at how sc.variable is used throughout the (original) Sitecore.config, it is almost always in places that would differ by environment. So the config defines a sc.variable for dataFolder for instance, and then an actual setting for it later like <setting name="dataFolder" value="$(dataFolder" />.

The reason for this is, that you can then isolate all the environment specific settings in your solution, and have a simple patch for them. All sc.variable declarations would be at the top of the config file, so they could be easily found and replaced.

I don't often see this used any more however. Sitecore later introduced config patching and I think, generally, people just use different layers of patch config files to achieve the same result; making the use of sc.variable largely obsolete.

Further reading:

• Manage Sitecore config across environments (DTAP)
• Improve the security of the website folder

Answer 3

Here is how I used Sitecore PowerShell Extensions to read a specific variable value.

$config = [Sitecore.Configuration.Factory]::GetConfiguration()
$speSourceFolder = $config.sitecore."sc.variable" | 
    Where-Object { $_.Name -eq "speSourceFolder" } | 
    Select-Object -First 1 -Expand value