I'm fairly new to AWS. I'm trying to pass a path parameter to my Lambda function like if I do a request:
PUT /users/{identity_id}
and pass in the the body below parameters
{
"name": "shikasta_kashti",
"age": 35
}
then I cannot get event.identity_id in my lambda function. I'm able to access event.name and event.age but not event.identity_id?
I think I would have to do some Mapping Template so I went to my PUT method and in Integration Request -> Mapping Templates added application/json and then selected Mapping Template (instead of Input passthrough) and entered this:
{
"identity_id": "$input.params('identity_id')",
}
but I still cannot get event.identity_id in my Lambda function.
Late response for someone stumbling on this...
The path params are included under event.pathParameters.
Given the request PUT /users/1 you would see a pathParameters object that looks like:
{
"identity_id": 1
}
If you didn't call your function with invoke you'll find the rest of your params in the event.body hash as a string.
To access that you'll do:
const { name, age} = JSON.parse(event.body)
Related
I need to pass a path param in the API.
By using the mapping template, I am able to pass query params and use them in the function.
Mapping template:
{
"Id": "$input.params('Id')" //this works fine after passing params as <url>?param=vale
}
With reference to this I created the mapping template as following-
{
"Id": "$input.params().querystring.get('Id')" // requirement is to be able to use <url>/value
}
I tried using 'Method request template' under genrate template, but it didn't work either.
When I invoke the URL urlname.execute-api.us-east-2.amazonaws.com/stag/functionname, it gives the value as undefined.
This is how I'm using the param:
class Lambda {
static run(event, context, callback) {
callback(null, 'Id '+ event.Id);
}
}
module.exports = Lambda;
Also, please tell me how to use those params in code.
Be kind :)
In order to be able to use <url>/value and get value from event follow this (Tested):
Configure your API gateway resource
Under /api2/{id} - GET - Integration Request configure your Mapping Templates
Execute request https://123456.execute-api.my-region.amazonaws.com/stage/api2/123
Lambda
console.log(event.id)
callback(null, {
id:event.id
});
CloudWatch
Hope this helps
How do I refer to API Gateway GET query string parameters in a Lambda function ?
When I test I can use my local test event with "username": "larry"
When I test with a post I can use the body parameters as the event with "username": "larry"
With a get request, I don't have a body. How could I use query string parameters and then refer to them in the request. What event or other attribute do I use to get at the query param or what setting or change do I need to make?
Method request
Integration request
Query String
When testing I've referred to event["username", what do I do for an API request passing it as a query string parameter?
Login and click to API gateway and click on method - GET method
Go to Method Execution - select URL Query String Parameter and add query String parameter username
Now go to Integration Request tab Choose Body Mapping Template,
"content type application/json"
Generate Template like below
{
"username": "$input.params('username')"
}
Now write ;ambda which accept key value in pair .
module.exports.get = (event, context, callback) => {
const { username } = event.pathParameters;
console.log("username", username);
}
Now go and deploy your api on apigetway and find url and hit in browser example
https://xxx.yyy-api.us-east-2.amazonaws.com/prod/username?vaquarkhan
Hope it will help
https://docs.aws.amazon.com/de_de/apigateway/latest/developerguide/welcome.html
https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-set-up-simple-proxy.html#api-gateway-set-up-lambda-proxy-integration-on-proxy-resource
I have a lambda, written in Java, that accepts a Request Object of the structure
{
"id": "be1c320a-144f-464d-b32c-38ec7fb4445b",
"userId": "foobar"
}
When I call this Lambda through the test interface with such an object, it works fine.
I want to create an API where a GET request to
/users/foobar/items/be1c320a-144f-464d-b32c-38ec7fb4445b
i.e. of the form
/users/{userId}/items/{id}
calls this Lambda.
I have created the API resources /users, {userId}, items, and {id} appropriately.
And I have created the GET method (on /users/{userId}/items/{id})and associated it to the lambda.
When I test the API, it invokes the lambda, but with null values in the request. I can see it package the path as {"id":"be1c320a-144f-464d-b32c-38ec7fb4445b","userId": "foobar"} in the logs, but that's not being sent in the body.
I have tried creating a template map (and have tried RTFM), but cannot see how to map path parameters to a body.
How do I achieve this mapping?
I think your Request Object structure may not be properly configured. There may be a few ways to configure this. Here is some information that has helped me.
How to pass a querystring or route parameter to AWS Lambda from Amazon API Gateway - Demonstrates this mapping (albeit with python). However, taking the top response, if you enable "Use Lambda Proxy integration", you can similarily do this with Java as so:
#Override
public Object handleRequest(APIGatewayProxyRequestEvent input, Context context) {
Map<String, String> pathParameters = input.getPathParameters();
String id = pathParameters.get("id");
String userId = pathParameters.get("userId");
// Handle rest of request..
}
This is a tuturial using the serverless framework to create an Api with Java. This tutorial similarily accesses the pathParameters by parsing the input rather than using the APIGatewayProxyRequestEvent java class.
#Override
public Object handleRequest(Map<String, Object> input, Context context) {
try {
// get the 'pathParameters' from input
Map<String,String> pathParameters = (Map<String,String>)input.get("pathParameters");
String id = pathParameters.get("id");
String userId = pathParameters.get("userId");
} catch (Exception ex) {
logger.error("Error in retrieving product: " + ex);
}
}
Use a mapping template.
First, in the Method Request section, you should see userId and id as Request Paths
Then, in the Integration Request, do not choose Proxy Integration.
Then in the Mapping Templates section, add a new mapping template for application/json of the form
{
"id" : "$method.request.path.id",
"userId" : "$method.request.path.user_id"
}
I have a Lambda function which is called through an API Gateway using a URL. I need to return a variation of the request's URL by which the Lambda function was originally called in the response. How can I find the URL of the request in a Lambda function?
I was hoping I can pass the URL as a parameter to the Lambda function using API Gateway's mapping template. But I don't see how I can do so!
This body mapping template should give you all you need:
{
"host" : "$input.params('Host')",
"path" : "$context.path"
}
So, for where the url called was 'xxxxxxxxxx.execute-api.us-east-1.amazonaws.com/stage/resource', this will pass an event into Lambda that looks like this:
{
host: 'xxxxxxxxxx.execute-api.us-east-1.amazonaws.com',
path: '/stage/resource'
}
If you are using the Use Lambda Proxy integration you can piece it together from the event properties. This is how I did it in python:
host = event["headers"]["Host"]
path = event["requestContext"]["path"]
proto = event["headers"]["X-Forwarded-Proto"]
request_url = f"{proto}://{host}{path}"
My api is of the form:
https://<>.execute-api.us-east-1.amazonaws.com/Testing/api/v1/mobs/<>.json?filename=<>.json&assertion=1
Currently, I have just defined till the .../mobs/<>.json in my Mapping Template, like this:
{
"mob_type": "$input.params('type')"
}
Now, I added query parameters to the url, which are filename and assertion. So, how do I define them in the Body Mapping Template?
This, doesn't work:
{
"mob_type": "$input.params('type')"
"filename": "$input.params('filename')"
"assertion": "$input.params('assertion')"
}
In the Integration Request under "URL Query String Parameters", you need to add a mapping for
method.request.querystring.type
method.request.querystring.filename
method.request.querystring.assertion
http://docs.aws.amazon.com/apigateway/latest/developerguide/request-response-data-mappings.html#mapping-request-parameters
With the mapping, they are accessible in the Body Mapping Templates.