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Author's profile photo Mayank Sood

Relationship Between Form-Data and SAP CPI, SuccessFactors Integration with AWS S3 bucket using POST method in “Form-Data”

Dear Reader,

Introduction: 

In this blog post I will be focusing on a recent requirement of placing a CSV file in AWS S3 bucket using POST request in form-data, the challenges faced during the execution and it’s solution.

Requirement:

We were supposed to place .csv file to AWS S3 bucket which accepts only POST request to be sent in form-data, but before this we had to call another API to get the curl request/form-data parameters, in which we send a request in JSON format with API-Key(in header for authentication) and filename, number of rows and content-type(in the body part for validation of data), in response we get more parameters such as “file ID”, “upload URL” and few other fields including the AWS security tokens etc. These all parameters we would in turn need to use in our final request were in we will be finally posting the file to.

What is Form-Data?

Before we jump on to the solution we must understand what actually is Form-Data?.

The FormData interface provides a way to easily construct a set of key/value pairs representing form fields and their values, which can then be easily sent using the fetch() or XMLHttpRequest.send() method. It uses the same format a form would use if the encoding type were set to “multipart/form-data”.

For more information you may refer below link:

https://developer.mozilla.org/en-US/docs/Web/API/FormData

Solution:

Overall CPI Design:

iFlow%20Screenshot

iFlow Screenshot

iFlow Part 1: This part deals with fetching the Employee’s Data from SuccessFactors and converting it to target system accepted format and segregating valid and invalid records as per business requirement and converting the data received from SuccessFactors from XML to CSV.

Part%201

Part 1

 

Iflow Part 2: This part deals with sending the first request and getting the unique parameters from AWS (Discussed below), converting the JSON received to XML  and storing all the values in properties and replacing the special characters (Discussed in the last segment) and in the end posting the final output(CSV) in a Form-Data to AWS S3 bucket via HTTP adapter using POST method.

 

Iflow%20Part%202

Iflow Part 2

Step 1: The very first step is to extract all the relevant data from SuccessFactors and create a .csv file as per the required structure and store the data in a property and store the count of the employees in a Content Modifier as we will be needing this while creating the first request to the endpoint URL.

Step 2: Once this is done, we need to create a “Request” in JSON format as explained in the “Requirement” section. Our Request looked like this:

{
  “filename”: “T_Employee_YYYYMMDDhhmmss.csv”,
  “rowCount”: “<number of records>(e.g. 10)”,
“contentType”: “text/csv”
}
Content%20Modifier%20for%20creating%20Request
This can we be easily accomplished using a Content Modifier and in the same Content Modifier you can set the Header as well for passing the API Key for authentication purpose. Parameter “rowCount” will be dynamic in nature, which will be passed as per the number of rows/Employee records fetched from SuccessFactors.

Step 3: Once step 2 is completed, we will then be getting a response with all the AWS security parameters such as unique “fileID” , “uploadURL” along with other fields in JSON format which needs to be passed in the form-data of the final request for the successful upload of the file in AWS S3. I have then converted the JSON structure to XML for storing the values in a property using XPath in Content Modifier, so that I can dynamically pass the same in my final request part.

Sample Response looked like below:

{
    “fileId”: “<uniqueFileID>”,
    “uploadUrl”: “<uploadURL”,
    “fields”: {
        “acl”: “<accessDetails>”,
        “x-amz-meta-filename”: “<fileName passed in earlier request>”,
        “x-amz-meta-rowcount”: “<number of records>(e.g. 10)”,
        “x-amz-meta-identity”: “<apiKey>”,
        “Content-Type”: “text/csv”,
        “key”: “<uniqueKey>”,
        “x-amz-algorithm”: “<AWSalgorithm>”,
        “x-amz-credential”: “<credentials>”,
        “x-amz-date”: “<date>”,
        “x-amz-security-token”: “<uniqueToken>”,
        “policy”: “<policy>”,
        “x-amz-signature”: “<signature>”
    },
    “curl”: “<curlRequest>”
}
Step 4: In a Content Modifier define a Header with Name: “Content-Type” and set the value to “multipart/form-data; boundary=——CPI” (——CPI can be replaced by anything as per your choice).
Once done, Now it’s time to create the final POST form-data Request  and the most trickiest part of the integration. I have used another Content Modifier for creating the final request which would look similar to the one we get it from Postman’s Code Snippet.
Content Modifier Body would look like below:

——–CPI
Content-Disposition: form-data; name=”acl”

${property.acl}
——–CPI
Content-Disposition: form-data; name=”x-amz-meta-filename”

${property.x-amz-meta-filename}
——–CPI
Content-Disposition: form-data; name=”x-amz-meta-rowcount”

${property.EmployeeCount}
——–CPI
Content-Disposition: form-data; name=”x-amz-meta-identity”

${property.x-amz-meta-identity}
——–CPI
Content-Disposition: form-data; name=”Content-Type”

${property.Content-Type1}
——–CPI
Content-Disposition: form-data; name=”key”

${property.key}
——–CPI
Content-Disposition: form-data; name=”x-amz-algorithm”

${property.x-amz-algorithm}
——–CPI
Content-Disposition: form-data; name=”x-amz-credential”

${property.x-amz-credential}
——–CPI
Content-Disposition: form-data; name=”x-amz-date”

${property.x-amz-date}
——–CPI
Content-Disposition: form-data; name=”x-amz-security-token”

${property.x-amz-security-token}
——–CPI
Content-Disposition: form-data; name=”policy”

${property.policy}
——–CPI
Content-Disposition: form-data; name=”x-amz-signature”

${property.x-amz-signature}
——–CPI
Content-Disposition: form-data; name=”file”; filename=”${property.x-amz-meta-filename}”
Content-Type: text/csv

${property.payload}
——–CPI–

Please Note: Use the same boundary value that we declared and add 2 sperate dashes. As I used 6 dashes in the Content-Type Header and in the request I used 8.

Here ${property.payload} is the final CSV payload that we have stored in Step 1. I had to use  filename=”${property.x-amz-meta-filename}” and “Content-Type: text/csv” parameter just before inserting the CSV data as I have to send a CSV file.

Content%20Modifier%20for%20Final%20Request

Content Modifier for Final Request

Major Issues Faced

The formatting of the final form-data POST request was one of the major issue that we faced while doing the integration. We realized that the request in unable to get processed due to special characters. As CPI creates UNIX line endings(\n) but AWS was expecting the line endings of windows (\r\n), then I had to write Groovy to replace all ‘\n’ with ‘\r\n. Below is the groovy for your reference.

import com.sap.gateway.ip.core.customdev.util.Message;
import java.util.HashMap;
def Message processData(Message message) {
    //Body 
       def body = message.getBody(String);
       body = body.replaceAll("\n", "\r\n");
       message.setBody(body);
       return message;
}

 

Conclusion: 

In this blog post we discussed how we can send a CSV file from SuccessFactors via SAP CPI to AWS S3 bucket using Form-Data via HTTP POST method.

Do comment in case you need any further clarification/information on the same. I would be very happy to assist and provide information as required.

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