How to change connection string automatically on build with Nant

Question

Hi, is it possible to change the connection string in my web.config automatically when build type is release using Nant? if so, how? thanks

Answer 1

I assume that you want to do this in order to have the connection string point out a production environment rather than development or test environment when Nant builds the release code. I usually have a different approach to solve this scenario; keep the connection strings in a separate file. You can do this by using the configSource attribute:

<!-- point out a file containing the connectionStrings config section -->
<connectionStrings configSource="connections.config"></connectionStrings>

The connections.config file should look something like this:

<?xml version="1.0"?>
<connectionStrings>
    <add name="myDb" connectionString="{your connection string}"/>
</connectionStrings>

Since the connection strings rarely change in the production environment, the file connections.config can then typically be excluded from the deployment.

Answer 2

I think you could use the xmlpoke task. For example, if your web.config is

<?xml version="1.0"?>
<configuration>
    <connectionStrings>
     <add name="myDb" connectionString="blah" providerName="blah"/>
    </connectionStrings>
</configuration>

Then you could add a task to your build file like this.

<xmlpoke 
    file="path_to_your_web_root\Web.config"
    xpath="/configuration/connectionStrings/add[@name='myDb']/@connectionString"
    value="your_connection_string" />

Oh, here is the documentation of the xmlpoke task. http://nant.sourceforge.net/release/latest/help/tasks/xmlpoke.html

Answer 3

I use a simple way. I prepared many versions of the config file, each contains its own connection strings (DEV, TEST, PRODUCTION). In NANT script, when I author different targets, I copy the specific config file to overwrite the default one.

Answer 4

Another alternative is to use a template where you have a token in place of the connection string e.g.

<connectionString>
   <add name="myDb" connectionString="@CONNECTION_STRING@" />
</connectionStrings>

Then use filterchains to replace this with the appropriate string.

<copy file="Web.config.template" tofile="Web.config" overwrite="true">
<filterchains>
    <replacetokens>
        <token key="CONNECTION_STRING" value="${ConnectionString}" />
    </replacetokens>
</filterchains>

The value of the ConnectionString property will vary according to the build type.

Filterchains are described in the Nant Documentation