**cURL Request:**

POST /api/v1/book/info HTTP/1.1
Host: www.perfectaudit.com
Authorization: Basic Y2hpdGl6QGxlbmRpbmd4bC5jb206U3VjY2Vzc0AxMDE=
Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW
Cache-Control: no-cache
Postman-Token: 875af4d4-616e-156f-1af1-d67fd925217a

------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="pk"

71704
------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="upload"; filename="eStmt_2017-11-30 (1).pdf"
Content-Type: application/pdf


------WebKitFormBoundary7MA4YWxkTrZu0gW--


**Response**

{"status": 400, "message": "required key not provided @ data['pk']", "code": 1003}

**HTTP Request in Apex:**

String boundary = '------WebKitFormBoundary7MA4YWxkTrZu0gW';
String header = boundary+'nContent-Disposition: form-data; name="pk"nn'+bookId;
`enter code here`header += 'n'+boundary+'nContent-Disposition: form-data; name="upload"; filename="'+file_name+'"nContent-Type: application/pdf'; //application/octet-stream multipart/form-data //pk="'+bookId+'";

            System.debug('header>>> '+header);
            // GW: Do not prepend footer with rn, you'll see why in a moment
            // String footer = 'rn--'+boundary+'--';
            String footer = 'nnn'+boundary+'--';
            String headerEncoded = EncodingUtil.base64Encode(Blob.valueOf(header+'rnrn'));
            while(headerEncoded.endsWith('=')){
                header+=' ';
                headerEncoded = EncodingUtil.base64Encode(Blob.valueOf(header+'rnrn'));
            }


            String bodyEncoded = EncodingUtil.base64Encode(file_body);


            // GW: Do not encode footer yet
            // String footerEncoded = EncodingUtil.base64Encode(Blob.valueOf(footer));

            Blob bodyBlob = null;
            String last4Bytes = bodyEncoded.substring(bodyEncoded.length()-4,bodyEncoded.length());

            // GW: Replacing this entire section

            // GW: replacement section to get rid of padding without corrupting data
            if(last4Bytes.endsWith('==')) {
                // The '==' sequence indicates that the last group contained only one 8 bit byte
                // 8 digit binary representation of CR is 00001101
                // 8 digit binary representation of LF is 00001010
                // Stitch them together and then from the right split them into 6 bit chunks
                // 0000110100001010 becomes 0000 110100 001010
                // Note the first 4 bits 0000 are identical to the padding used to encode the
                // second original 6 bit chunk, this is handy it means we can hard code the response in
                // The decimal values of 110100 001010 are 52 10
                // The base64 mapping values of 52 10 are 0 K
                // See http://en.wikipedia.org/wiki/Base64 for base64 mapping table
                // Therefore, we replace == with 0K
                // Note: if using nn instead of rn replace == with 'oK'
                last4Bytes = last4Bytes.substring(0,2) + '0K';
                bodyEncoded = bodyEncoded.substring(0,bodyEncoded.length()-4) + last4Bytes;
                // We have appended the rn to the Blob, so leave footer as it is.
                String footerEncoded = EncodingUtil.base64Encode(Blob.valueOf(footer));
                bodyBlob = EncodingUtil.base64Decode(headerEncoded+bodyEncoded+footerEncoded);
            } else if(last4Bytes.endsWith('=')) {
                // '=' indicates that encoded data already contained two out of 3x 8 bit bytes
                // We replace final 8 bit byte with a CR e.g. r
                // 8 digit binary representation of CR is 00001101
                // Ignore the first 2 bits of 00 001101 they have already been used up as padding
                // for the existing data.
                // The Decimal value of 001101 is 13
                // The base64 value of 13 is N
                // Therefore, we replace = with N
                // Note: if using n instead of r replace = with 'K'
                last4Bytes = last4Bytes.substring(0,3) + 'N';
                bodyEncoded = bodyEncoded.substring(0,bodyEncoded.length()-4) + last4Bytes;
                // We have appended the CR e.g. r, still need to prepend the line feed to the footer
                footer = 'n' + footer;
                String footerEncoded = EncodingUtil.base64Encode(Blob.valueOf(footer));
                bodyBlob = EncodingUtil.base64Decode(headerEncoded+bodyEncoded+footerEncoded);
            } else {
                // Prepend the CR LF to the footer
                footer = 'rn' + footer;
                String footerEncoded = EncodingUtil.base64Encode(Blob.valueOf(footer));
                bodyBlob = EncodingUtil.base64Decode(headerEncoded+bodyEncoded+footerEncoded);
            }

            HttpRequest req = new HttpRequest();

            String userName = ocrolusSettings.lendingxl__UserName__c;
            String password = ocrolusSettings.lendingxl__Password__c;
            Blob headerValue = Blob.valueOf(userName+ ':' +password);
            String authorizationHeader = 'Basic ' +EncodingUtil.base64Encode(headerValue);
            System.debug('authorizationHeader>>>'+authorizationHeader);
            req.setHeader('Authorization', authorizationHeader);

            System.debug('boundary>>>'+boundary);

            req.setHeader('Content-Type','multipart/form-data; boundary='+boundary);

            //req.setHeader('Content-Type','multipart/form-data; boundary='+headerEncoded);
            req.setMethod(method);
            req.setEndpoint(ocrolusSettings.lendingxl__EndPoint__c+ resourceName);//
            //req.setEndpoint(reqEndPoint);
            req.setBodyAsBlob(bodyBlob);
            req.setTimeout(120000);

            Http http = new Http();

            System.debug('req>>> '+req);
            HTTPResponse res = http.send(req);
            response =res.getBody();