fix PHP Post

[atrope]

Hi,
Testing in our environment we found a bug when sending the content-length Header via ALB.
The curl call stucks which i think it's a bug: https://stackoverflow.com/questions/9340734/php-curl-data-not-posted-if-headers-are-set

I Managed to fix by making the header on-the fly with the actual sent body.
For this i changed the order where we call the CURLOPT_HTTPHEADER to after the $body variable is defined.

[txase]

While this does paper over the issue, it also is weirdly overriding specific behavior (setting the Content-Length header to a certain value).

I'd like to know more about why the Content-Length header is set incorrectly before overriding its value. Why is the built-in php webserver returning 0 for the response body length?

[atrope]

hey @txase I Think it is a PHP CURL known-bug...
As you can see the Stack Overflow link I sent here is from 2012 and it still happens..

[txase]

The SO link says: If you want to send a request body, make sure to set the Content-Length header to the length of the body.

This change does something different. It overrides the Content-Length header value that is provided in the request. We can do that, but it's probably a sign that the client simply is making an invalid request.

Since this is coming through an ALB, can you get a dump of the request (including headers and body) sent to the ALB so we can verify whether it is setting the Content-Length header appropriately?

[atrope]

Hey @txase,
I AM also investigating here and trying another approach.
Here a dump of a the Events:

{
    "requestContext": {
        "elb": {
            "targetGroupArn": "arn:aws:elasticloadbalancing:us-east-1:272581579102:targetgroup/portal-sls/57c57ec773305a80"
        }
    },
    "httpMethod": "POST",
    "path": "/verificar/short",
    "multiValueQueryStringParameters": [],
    "multiValueHeaders": {
        "accept": [
            "*/*"
        ],
        "accept-encoding": [
            "gzip, deflate"
        ],
        "cache-control": [
            "no-cache"
        ],
        "connection": [
            "keep-alive"
        ],
        "content-length": [
            "169"
        ],
        "content-type": [
            "multipart/form-data; boundary=--------------------------490608822155697904763973"
        ],
        "cookie": [
            "SMSession=07f5d0d3a5f913bf2e8ccfe596606934"
        ],
        "host": [
            "sls.suamusica.com.br"
        ],
        "postman-token": [
            "ff36a950-4215-472a-af75-fbd1a0f079e5"
        ],
        "user-agent": [
            "PostmanRuntime/7.1.1"
        ],
        "x-amzn-trace-id": [
            "Root=1-5c07894f-e53a5ac0f74561e24599f662"
        ],
        "x-forwarded-for": [
            "213.57.219.40"
        ],
        "x-forwarded-port": [
            "443"
        ],
        "x-forwarded-proto": [
            "https"
        ]
    },
    "body": "LS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLTQ5MDYwODgyMjE1NTY5NzkwNDc2Mzk3Mw0KQ29udGVudC1EaXNwb3NpdGlvbjogZm9ybS1kYXRhOyBuYW1lPSJ1c2VybmFtZSINCg0KYXRyb3BlDQotLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tLS0tNDkwNjA4ODIyMTU1Njk3OTA0NzYzOTczLS0NCg==",
    "isBase64Encoded": true
}

{
    "resource": "/{proxy+}",
    "path": "/verificar/short",
    "httpMethod": "POST",
    "headers": {
        "Accept": "*/*",
        "Accept-Encoding": "gzip, deflate",
        "cache-control": "no-cache",
        "CloudFront-Forwarded-Proto": "https",
        "CloudFront-Is-Desktop-Viewer": "true",
        "CloudFront-Is-Mobile-Viewer": "false",
        "CloudFront-Is-SmartTV-Viewer": "false",
        "CloudFront-Is-Tablet-Viewer": "false",
        "CloudFront-Viewer-Country": "IL",
        "Content-Type": "multipart/form-data; boundary=--------------------------227495847972197776776649",
        "Host": "2taxm30w7g.execute-api.us-east-1.amazonaws.com",
        "Postman-Token": "a31df53e-32ef-4d10-9041-c619f9de8cdf",
        "User-Agent": "PostmanRuntime/7.1.1",
        "Via": "1.1 6e3453a91a5fc5982955003a408b061d.cloudfront.net (CloudFront)",
        "X-Amz-Cf-Id": "-CoK-i6IFc0oh_J9AN-3aZOUSh4VH6uj0Z7NTP7QRrLadOyGP2cPlQ==",
        "X-Amzn-Trace-Id": "Root=1-5c078961-5ebe587cacf42d94f18652a8",
        "X-Forwarded-For": "213.57.219.40, 70.132.15.83",
        "X-Forwarded-Port": "443",
        "X-Forwarded-Proto": "https"
    },
    "multiValueHeaders": {
        "Accept": [
            "*/*"
        ],
        "Accept-Encoding": [
            "gzip, deflate"
        ],
        "cache-control": [
            "no-cache"
        ],
        "CloudFront-Forwarded-Proto": [
            "https"
        ],
        "CloudFront-Is-Desktop-Viewer": [
            "true"
        ],
        "CloudFront-Is-Mobile-Viewer": [
            "false"
        ],
        "CloudFront-Is-SmartTV-Viewer": [
            "false"
        ],
        "CloudFront-Is-Tablet-Viewer": [
            "false"
        ],
        "CloudFront-Viewer-Country": [
            "IL"
        ],
        "Content-Type": [
            "multipart/form-data; boundary=--------------------------227495847972197776776649"
        ],
        "Host": [
            "2taxm30w7g.execute-api.us-east-1.amazonaws.com"
        ],
        "Postman-Token": [
            "a31df53e-32ef-4d10-9041-c619f9de8cdf"
        ],
        "User-Agent": [
            "PostmanRuntime/7.1.1"
        ],
        "Via": [
            "1.1 6e3453a91a5fc5982955003a408b061d.cloudfront.net (CloudFront)"
        ],
        "X-Amz-Cf-Id": [
            "-CoK-i6IFc0oh_J9AN-3aZOUSh4VH6uj0Z7NTP7QRrLadOyGP2cPlQ=="
        ],
        "X-Amzn-Trace-Id": [
            "Root=1-5c078961-5ebe587cacf42d94f18652a8"
        ],
        "X-Forwarded-For": [
            "213.57.219.40, 70.132.15.83"
        ],
        "X-Forwarded-Port": [
            "443"
        ],
        "X-Forwarded-Proto": [
            "https"
        ]
    },
    "queryStringParameters": null,
    "multiValueQueryStringParameters": null,
    "pathParameters": {
        "proxy": "verificar/short"
    },
    "stageVariables": null,
    "requestContext": {
        "resourceId": "s2dnay",
        "resourcePath": "/{proxy+}",
        "httpMethod": "POST",
        "extendedRequestId": "RbJnPGDcoAMFwfg=",
        "requestTime": "05/Dec/2018:08:16:33 +0000",
        "path": "/dev/verificar/short",
        "accountId": "272581579102",
        "protocol": "HTTP/1.1",
        "stage": "dev",
        "domainPrefix": "2taxm30w7g",
        "requestTimeEpoch": 1543997793514,
        "requestId": "13ab354d-f866-11e8-be40-dbd7ab2d94ee",
        "identity": {
            "cognitoIdentityPoolId": null,
            "accountId": null,
            "cognitoIdentityId": null,
            "caller": null,
            "sourceIp": "213.57.219.40",
            "accessKey": null,
            "cognitoAuthenticationType": null,
            "cognitoAuthenticationProvider": null,
            "userArn": null,
            "userAgent": "PostmanRuntime/7.1.1",
            "user": null
        },
        "domainName": "2taxm30w7g.execute-api.us-east-1.amazonaws.com",
        "apiId": "2taxm30w7g"
    },
    "body": "----------------------------227495847972197776776649\r\nContent-Disposition: form-data; name=\"username\"\r\n\r\natrope\r\n----------------------------227495847972197776776649--\r\n",
    "isBase64Encoded": false
}

[txase]

The ALB event has the correct content-length value. The api gateway event is missing the content-length. I would expect the ALB request to work, but the api gateway request not to. But you're saying the ALB request is not working, while the api gateway is working?

[atrope]

@txase you are correct.. I Have no idea why, and i agree it should not be treated as "official" fix..
It does fix the issue, so in my layer i changed it.

I Will keep checking if we can solve this in another way.

Feel free to close the PR if you wish

[txase]

That's very strange. I'm going to close this PR as there doesn't seem to be evidence that the layer itself is doing something wrong, but please re-open if you make any progress on the core issue!