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Building functions

Below is a high-level overview of how to structure your Buildfunctions handler functions and their responses. The various examples demonstrate a consistent pattern: a main entry point function named handler that returns (or echoes) a response containing at least a body. Beyond that, you can optionally include a status code and headers in the natural syntax the language supports.

1. The handler Function

• Naming: Your main function must be named handler. This name is how Buildfunctions identifies which function to invoke when your code runs.
• Purpose: The handler function is your function’s entry point. It contains the logic you want to run whenever your function is invoked. You can write other helper functions, but only the handler will be called automatically.

2. The Response Format

Your handler function must provide a response that can be returned to the caller. While the exact syntax differs by language, the structure is essentially the same:

• Body (Required): The main content you want to return.
• Status Code (Optional): A numeric HTTP status code (e.g., 200 for success, 500 for a server error).
• Headers (Optional): Custom headers, such as Content-Type, can also be included.

Example Response Structures:

• JavaScript

  async function handler(event) {
    return {
      statusCode: 200,
      headers: { 'Content-Type': 'text/plain' },
      body: 'Hello, world!',
    };
  }

• TypeScript

  async function handler(event: any): Promise<{
    statusCode: number;
    headers: { [key: string]: string };
    body: string;
  }> {
    return {
      statusCode: 200,
      headers: { 'Content-Type': 'text/plain' },
      body: 'Hello, world!',
    };
  }

• Python

  def handler(event, context):
      return {
          "statusCode": 200,
          "headers": {"Content-Type": "text/plain"},
          "body": "Hello, world!"
      }

• Go

  package handler
  
  import "fmt"
  
  func handler() string {
      fmt.Println("Hello, world!")
      return "Hello, world!"
  }

• Shell

  handler() {
      echo "Hello, world!"
  }

• Python

  def handler(event, context):
      return {
          "statusCode": 200,
          "headers": {"Content-Type": "text/plain"},
          "body": "Hello, world!"
      }
  
  # Do NOT include:
  # if __name__ == "__main__":
  #    response = handler()
  #    print(response)
  

• JavaScript

  function handler() {
    return {
      statusCode: 200,
      headers: { 'Content-Type': 'text/plain' },
      body: 'Hello, world!',
    };
  }
  
  // Do NOT include:
  // handler(); // Unnecessary;
  

Note: Buildfunctions is currently in its beta stage. If you encounter any issues or have specific syntax requirements, please reach out and contact us, and we’ll work to address them.