upload.cfc

<cfcomponent>

  <cffunction name="upload" access="remote" returntype="struct" returnformat="json" output="false">
    <cfscript>
      var uploadDir = expandPath('.') & '/uploads/'; // should be a temp directory that you clear periodically to flush orphaned files 
      var uploadFile =  uploadDir & arguments.NAME;
      var response = {'result' = arguments.NAME, 'id' = 0};
      var result = {};
      // if chunked append chunk number to filename for reassembly
      if (structKeyExists(arguments, 'CHUNKS')){
        uploadFile = uploadFile & '.' & arguments.CHUNK;
        response.id = arguments.CHUNK;
      }
    </cfscript>		
		
    <!--- save file data from multi-part form.FILE --->
    <cffile action="upload" result="result" filefield="FILE" destination="#uploadFile#" nameconflict="overwrite"/>
		
    <cfscript>
      // Example: you can return uploaded file data to client 
      response['size'] = result.fileSize;
      response['type'] = result.contentType;
      response['saved'] = result.fileWasSaved;
			
      // reassemble chunked file
      if (structKeyExists(arguments, 'CHUNKS') && arguments.CHUNK + 1 == arguments.CHUNKS){
        try {
          var uploadFile = uploadDir & arguments.NAME; // file name for reassembled file - if using a temp directory then this should be the final output path/file
          if (fileExists(uploadFile)){
            fileDelete(uploadFile); // delete otherwise append will add chunks to an existing file
          }

          var tempFile = fileOpen(uploadFile,'append');
          for (var i = 0; i < arguments.CHUNKS; i++) {
            var chunk = fileReadBinary('#uploadDir#/#arguments.NAME#.#i#');
            fileDelete('#uploadDir#/#arguments.NAME#.#i#');
            fileWrite(tempFile, chunk);
          }
          fileClose(tempFile);
	}
        catch(any err){
          // clean up chunks for incomplete upload
          var d = directoryList(uploadDir,false,'name');
          if (arrayLen(d) != 0){
            for (var i = 1; i <= arrayLen(d); i++){
              if (listFirst(d[i]) == arguments.NAME && val(listLast(d[i])) != 0){
                fileDelete('#uploadDir##d[i]#');
              }
            }
          }

          // you could add more error handling and return info from err 
          response = {'error' = {'code' = 500, 'message' = 'Internal Server Error'}, 'id' = 0};  
        }
      }
      return response;
    </cfscript>
  </cffunction>

</cfcomponent>