[975] Creating a POSTMAN Api | AWS API Gateway Passing Data to AWS Lambda
ref: Guide to AWS Lambda Function URLs
ref: Test your Lambda function with Postman
1. Create a Lambda Function
2. Edit basic settings
The internal error in Postman test, sometimes it's because the function's running time is too long. Change the timeout time can fix this error as follows.
Changing the timeout value is very important, otherwise the function often raise the issue of "internal sever errors"!!!
3. Create a Function URL
Configuration -> Function URL
Then, the Function URL is generated and can be seen from the upper right corner. Copy it!
4. Create a test POST in Postman
Paste the Function URL in the POST URL area and then click the Save
button.
Click the Send
button, then the test results will be shown below.
5. Add information in Params, Headers, and Body
6. Modify the lambda_function and show details of "event"
Test the lambda_function from the test case of Postman. The return information is show as below.
The details of output are as follows.
{
"event": {
"headers": {
"content-length": "59",
"x-amzn-tls-version": "TLSv1.2",
"x-forwarded-proto": "https",
"postman-token": "0f337b21-f35a-4b63-9904-423aea79304a",
"x-forwarded-port": "443",
"x-forwarded-for": "54.86.50.139",
"header_name": "Alex",
"accept": "*/*",
"header_country": "China",
"x-amzn-tls-cipher-suite": "ECDHE-RSA-AES128-GCM-SHA256",
"x-amzn-trace-id": "Root=1-65d3f694-5a37ccac4de9141818821224",
"host": "as2yuw3zjpqcankr7k4eteumme0bmnbz.lambda-url.ap-southeast-2.on.aws",
"content-type": "application/json",
"cache-control": "no-cache",
"accept-encoding": "gzip, deflate, br",
"user-agent": "PostmanRuntime/7.36.3"
},
"isBase64Encoded": false,
"rawPath": "/",
"routeKey": "$default",
"requestContext": {
"accountId": "anonymous",
"timeEpoch": 1708390036365,
"routeKey": "$default",
"stage": "$default",
"domainPrefix": "as2yuw3zjpqcankr7k4eteumme0bmnbz",
"requestId": "62ac7803-5d6b-4208-a8e9-c74647caa7a6",
"domainName": "as2yuw3zjpqcankr7k4eteumme0bmnbz.lambda-url.ap-southeast-2.on.aws",
"http": {
"path": "/",
"protocol": "HTTP/1.1",
"method": "POST",
"sourceIp": "54.86.50.139",
"userAgent": "PostmanRuntime/7.36.3"
},
"time": "20/Feb/2024:00:47:16 +0000",
"apiId": "as2yuw3zjpqcankr7k4eteumme0bmnbz"
},
"queryStringParameters": {
"Param_Country": "China",
"Param_Name": "Alex"
},
"body": "{\r\n \"Body_Name\": \"Alex\",\r\n \"Body_Country\": \"China\"\r\n}",
"version": "2.0",
"rawQueryString": "Param_Name=Alex&Param_Country=China"
}
}
From the lambda_function, we can extract detail values. Specifically, for the key of body
, the value of it is the type of string, we should convert it to the JSON format. Using json.loads()
function can extract the JSON file from the string.
7. Extract specific values from "event"
Get the values from the above JSON file in the lambda_function.
import json
def lambda_handler(event, context):
return {
# Headers
"Header_Name": event["headers"]["header_name"],
"Header_Country": event["headers"]["header_country"],
# Params
"Param_Name": event["queryStringParameters"]["Param_Name"],
"Param_Country": event["queryStringParameters"]["Param_Country"],
# Body
"Body_Name": json.loads(event["body"])["Body_Name"],
"Body_Country": json.loads(event["body"])["Body_Country"],
# "POST" or "GET"
"Type": event["requestContext"]["http"]["method"]
}
It will shows like this.
{
"Header_Name": "Alex",
"Type": "POST",
"Param_Country": "China",
"Body_Country": "China",
"Body_Name": "Alex",
"Header_Country": "China",
"Param_Name": "Alex"
}
8. Debug the codes in lambda_function
Monitor -> View CloudWatch logs -> Log groups -> Lambda Function Name -> Log streams
Using print()
function to test the code and it will be printed in the log streams as follows.