Hi,
I want to upload salesforce attachments to box.com account using Rest API. For authentication I am using Auth Provider. I have created a named credential "TestBox" which uses this Auth Provider and url "https://upload.box.com/api/2.0/".  I am able to uplaod .txt files using this. But while uploading .docx file it shows "Script-thrown exception".

I am able to upload .docx file by hardcoding Endpoint. But here I want to use named credentials. Can anyone help.

This is my code::


attachment file1= [SELECT Id, Name, Body FROM attachment where name like '%COS%' LIMIT 1];
system.debug('file1'+file1);
String x= uploadFileToBox('0', file1 ); 
system.debug('x'+x);
public static String uploadFileToBox(String strFolderId,attachment file)
{
    String fileId ;
    String boundary = '----------------------------741e90d31eff';
    String header = '--'+boundary+'\nContent-Disposition: form-data; name="file"; filename="'+file.name+'";\nContent-Type: multipart/form-data;'+'\nnon-svg='+True;
    String footer = '--'+boundary+'--';             
    String headerEncoded = EncodingUtil.base64Encode(Blob.valueOf(header+'\r\n\r\n'));
    //HttpResponse res;
    String strFileId;
    
    while(headerEncoded.endsWith('='))
    {
        header+=' ';
        headerEncoded = EncodingUtil.base64Encode(Blob.valueOf(header+'\r\n\r\n'));
    }
    
    String bodyEncoded = EncodingUtil.base64Encode(file.body);
    
    Blob bodyBlob = null;
    String last4Bytes = bodyEncoded.substring(bodyEncoded.length()-4,bodyEncoded.length());
    
    // GW: replacement section to get rid of padding without corrupting data
    if(last4Bytes.endsWith('==')) 
    {
        last4Bytes = last4Bytes.substring(0,2) + '0K';
        bodyEncoded = bodyEncoded.substring(0,bodyEncoded.length()-4) + last4Bytes;
        String footerEncoded = EncodingUtil.base64Encode(Blob.valueOf(footer));
        bodyBlob = EncodingUtil.base64Decode(headerEncoded+bodyEncoded+footerEncoded);
    }
    
    else if(last4Bytes.endsWith('=')) 
    {
        last4Bytes = last4Bytes.substring(0,3) + 'N';
        bodyEncoded = bodyEncoded.substring(0,bodyEncoded.length()-4) + last4Bytes;
        footer = '\n' + footer;
        String footerEncoded = EncodingUtil.base64Encode(Blob.valueOf(footer));
        bodyBlob = EncodingUtil.base64Decode(headerEncoded+bodyEncoded+footerEncoded);              
    } 
    
    else 
    {
        footer = '\r\n' + footer;
        String footerEncoded = EncodingUtil.base64Encode(Blob.valueOf(footer));
        bodyBlob = EncodingUtil.base64Decode(headerEncoded+bodyEncoded+footerEncoded);  
    }
    
    String sUrl = 'callout:TestBox/files/content?parent_id='+strFolderId;
    HttpRequest req = new HttpRequest();
    
    //req.setHeader('Content-Type','multipart/form-data;non_svg='+True+';boundary='+boundary);
    req.setHeader('Content-Type','application/msword');
    
    req.setMethod('POST');
    req.setEndpoint(sUrl);
    req.setBodyAsBlob(bodyBlob);
    req.setTimeout(60000);
      
    req.setHeader('Content-Length',String.valueof(req.getBodyAsBlob().size()));
    
    Http http = new Http();
    
    system.debug('*****size****'+req.getBodyAsBlob().size());
    
    if(Test.isRunningTest()) {
        
        // Create a fake response
        //res = new HttpResponse();
        //res.setStatusCode(201);
    }
    else {
        
        try{
            HttpResponse res = http.send(req);   
            System.debug('res = ' + res);
            System.debug('res = ' + res.getBody());
            
            Jsonparser parser = Json.createParser(res.getBody());
            system.debug('parser '+parser );
            while (parser.nextToken() != null) 
            {
                parser.nextValue();
                String fieldName = parser.getCurrentName();
                String fieldValue = parser.getText();
                
                if(fieldName == 'id')
                {
                    fileId = fieldValue;
                    system.debug('fileId '+fileId );
                    return fileId;
                }
            }                      
            return fileId; 
        }catch (System.CalloutException e){
            System.debug('ERROR:' + e);
        }
    }
    return fileId;
}


Thanks,

Adheena