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Available inall subroutines.

True if the string s begins with the string begins_with. An empty string is not considered a prefix.

Returns false otherwise.

Example

set req.http.X-ps = std.prefixof("greenhouse", "green");

Try it out

std.prefixof is used in the following code examples. Examples apply VCL to real-world use cases and can be deployed as they are, or adapted for your own service. See the full list of code examples for more inspiration.

Click RUN on a sample below to provision a Fastly service, execute the code on Fastly, and see how the function behaves.