How to include custom web.config files as part of package? - sharepoint-2010

Question

I'm a newbie at SharePoint 2010. I right-click on the project, select Deploy if I want to deploy locally. The Site URL on the project is set to my local machine. If I want to deploy to the QA server, I select Deploy, navigate to the Debug/Release folder, grab the .wsp file, logon to the Central Administration on QA, retract the solution, then do Add-SPsolution <path to wsp file> through powershell, go back to Central Admin, the click on Deploy solution for that package. Works fine.
The web.config on my local machine has a custom connection string, and appsettings. When I deploy the package on the QA server, I'm manually changing the connection string and appsettings specific to QA. I want to automate this process. I want the web.config to be part of the package with it's own custom connecting string (one for local, one for QA, and for Production) and appsettings. How do I do it? The goal is on a new machine, I should be able to deploy the wsp and appsettings+web.config should all be correct without modifying anything manually. How do I accomplish this?

Answer 1

I am pretty sure web.config modifications can't be done with just package files / CAML.
However, what can be done is to deploy a WebApplication Feature Reciever which modifies the web.config through SPWebApplication.WebConfigModifications.
Here is a snippet of code from my project, see the the Code Project KB for more details: (This first bit is just a handy function with some notes.)
// For WebConfigModifications access,
// see http://www.codeproject.com/KB/sharepoint/SPWebConfigModTool.aspx
// Hints:
// app.WebConfigModifications.Add(new SPWebConfigModification
// {
// Type = [add/update child node?]
// Path = [XPath of parent node]
// Name = [XPath to identify child node UNIQUELY]
// Owner = [Use GUID to identify as ours]
// Sequence = [Sequence number, likely 0 for only one]
// Value = [XML node to add/update]
// });
void ModfiyWebConfig (SPWebApplication app, string path, string name, XElement node)
{
app.WebConfigModifications.Add(new SPWebConfigModification
{
Type = SPWebConfigModificationType.EnsureChildNode,
Path = path,
Name = name,
Owner = OwnerId,
Sequence = 0,
Value = node.ToString(),
});
}
Get/init SPWebApplication
var app = properties.Feature.Parent as SPWebApplication;
Queue/setup modifications
ModfiyWebConfig(app,
"configuration/system.webServer/modules",
"add[#name='ASPxHttpHandlerModule']",
new XElement("add",
new XAttribute("name", "ASPxHttpHandlerModule"),
new XAttribute("type", aspxHandlerModule)));
Apply modifications
app.WebService.ApplyWebConfigModifications();
app.Update();