requestParameters returning "Invalid mapping expression specified: true"

Question

I'm configuring a lambda function's API gateway integration with the Serverless Framework version 0.4.2.

My problem is with defining an endpoint's request parameters. The AWS docs for API gateway entry says:

requestParameters

Represents request parameters that can be accepted by Amazon API Gateway. Request parameters are represented as a key/value map, with a source as the key and a Boolean flag as the value. The Boolean flag is used to specify whether the parameter is required. A source must match the pattern method.request.{location}.{name}, where location is either querystring, path, or header. name is a valid, unique parameter name. Sources specified here are available to the integration for mapping to integration request parameters or templates.

As I understand it, the config in the s-function.json is given directly to the AWS CLI, so I've specified the request parameters in the format: "method.request.querystring.startYear": true. However, I'm receiving an Invalid mapping expression specified: true error. I've also tried specifying the config as "method.request.querystring.startYear": "true" with the same result.

s-function.json:

{
    "name": "myname",
    // etc...
    "endpoints": [
        {
            "path": "mypath",
            "method": "GET",
            "type": "AWS",
            "authorizationType": "none",
            "apiKeyRequired": false,
            "requestParameters": {
                "method.request.querystring.startYear": true,
                "method.request.querystring.startMonth": true,
                "method.request.querystring.startDay": true,
                "method.request.querystring.currentYear": true,
                "method.request.querystring.currentMonth": true,
                "method.request.querystring.currentDay": true,
                "method.request.querystring.totalDays": true,
                "method.request.querystring.volume": true,
                "method.request.querystring.userId": true
            },
            // etc...
        }
    ],
    "events": []
}

Any ideas? Thanks in advance!

score 6 · Accepted Answer · edited May 23 '17 at 11:50

It looks like the requestParameters in the s-function.json file is meant for configuring the integration request section, so I ended up using:

"requestParameters": {
    "integration.request.querystring.startYear" : "method.request.querystring.startYear",
    "integration.request.querystring.startMonth" : "method.request.querystring.startMonth",
    "integration.request.querystring.startDay" : "method.request.querystring.startDay",
    "integration.request.querystring.currentYear" : "method.request.querystring.currentYear",
    "integration.request.querystring.currentMonth" : "method.request.querystring.currentMonth",
    "integration.request.querystring.currentDay" : "method.request.querystring.currentDay",
    "integration.request.querystring.totalDays" : "method.request.querystring.totalDays",
    "integration.request.querystring.volume" : "method.request.querystring.volume",
    "integration.request.querystring.userId" : "method.request.querystring.userId"
},

This ended up adding them automatically to the method request section on the dashboard as well:

I could then use them in the mapping template to turn them into a method post that would be sent as the event into my Lambda function. Right now I have a specific mapping template that I'm using, but I may in the future use Alua K's suggested method for mapping all of the inputs in a generic way so that I don't have to configure a separate mapping template for each function.

score 2 · Answer 2 · answered Mar 21 '16 at 11:53

2

You can pass query params to your lambda like

"requestTemplates": {
     "application/json": {
        "querystring": "$input.params().querystring"
      }
 }

In lambda function access querystring like this event.querystring

answered Mar 21 '16 at 11:53

Alua K

398
1
3
18

other better solution http://stackoverflow.com/a/33602122/2318357. But it does not involve sls. – Alua K Mar 21 '16 at 11:58
http://kennbrodhagen.net/2015/12/06/how-to-create-a-request-object-for-your-lambda-event-from-api-gateway/ – Alua K Mar 21 '16 at 11:58
I was more concerned about the syntax/format of the `requestParameters` for this question, but this is a good suggestion that I'll start using as well – Seafish Mar 23 '16 at 00:33

score 2 · Answer 3 · answered Apr 10 '20 at 18:07

First, you need to execute a put-method command for creating the Method- Request with query parameters:

aws apigateway put-method --rest-api-id "yourAPI-ID" --resource-id "yourResource-ID" --http-method GET --authorization-type "NONE" --no-api-key-required --request-parameters "method.request.querystring.paramname1=true","method.request.querystring.paramname2=true"

After this you can execute the put-integration command then only this will work. Otherwise it will give invalid mapping error

"requestParameters": {
    "integration.request.querystring.paramname1" : "method.request.querystring.paramname1",
    "integration.request.querystring.paramname2" : "method.request.querystring.paramname2",

score 0 · Answer 4 · answered Mar 21 '16 at 21:56

0

Make sure you're using the right end points as well. There are two types or some such in AWS.. friend of mine got caught out with that in the past.

answered Mar 21 '16 at 21:56

Paul Dunlop

327
1
5

requestParameters returning "Invalid mapping expression specified: true"

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