issue-16: fix download bug in data product delivery

onc/+onc/DataProductFile.m

@@ -64,7 +64,9 @@
             uri = matlab.net.URI(this.baseUrl);
             uri.Query = matlab.net.QueryParameter(this.filters);
             fullUrl = char(uri);
-            options = matlab.net.http.HTTPOptions('ConnectTimeout', timeout, 'ConvertResponse', false);
+
+            options = matlab.net.http.HTTPOptions('ConnectTimeout', timeout);
+
             while this.status == 202
                 % run and time request
                 if this.showInfo, log.printLine(sprintf('Requesting URL:\n   %s', fullUrl)); end
@@ -96,41 +98,44 @@
                     if length(lengthData) == 1
                         this.fileSize = str2double(lengthData.Value);
                     else
-                        this.fileSize = strlength(response.Body.Data);
+                        ext = util.extractFileExtension(filename);
+                        if strcmp(ext, 'xml')
+                            this.fileSize = length(xmlwrite(response.Body.Data));
+                        else
+                            this.fileSize = strlength(response.Body.Data);
+                        end
                     end
-
-                    savefilename = fullfile(outPath, filename);
-                    % Create folder if not exist
-                    if ~exist(outPath,'dir')
-                        mkdir(outPath)
-                    end
-                    % saveResult  -2: File exists and set to not overwrite 0: done
-                    if ~overwrite && exist(savefilename,'file') == 2
-                        saveResult = -2; 
-                    else
-                        websave(savefilename,uri.EncodedURI);
-                        saveResult = 0;
+                    try
+                        saveResult = util.save_as_file(response.Body.Data, outPath, filename, 'overwrite', overwrite);
+                    catch ME
+                        if strcmp(ME.identifier, 'onc:FileExistsError')
+                            log.printLine(sprintf('Skipping "%s": File already exists\n', this.fileName));
+                            this.status = 777;
+                            saveResult = -2;
+                            this.downloaded = false;
+                        else
+                            rethrow(ME);
+                        end
                     end
+
                     this.downloadingTime = round(duration, 3);
 
                     % log status
                     if saveResult == 0
                         log.printLine(sprintf('Downloaded "%s"\n', this.fileName));
-                    elseif saveResult == -2
-                        log.printLine(sprintf('Skipping "%s": File already exists\n', this.fileName));
-                        this.status = 777;
                     end
                 elseif s == 202
                     % Still processing, wait and retry
-                    log.printResponse(jsondecode(response.Body.Data));
+                    log.printResponse(response.Body.Data);
                     pause(pollPeriod);
                 elseif s == 204
                     % No data found
                     log.printLine('No data found.\n');
                 elseif s == 400
                     % API Error
                     util.print_error(response, fullUrl);
-                    throw(util.prepare_exception(s, double(jsondecode(response.Body.Data).errors.errorCode)));
+                    throw(util.prepare_exception(s, double(response.Body.Data.errors.errorCode)));
+
                 elseif s == 404
                     % Index too high, no more files to download
                 else

onc/+util/extractFileExtension.m

@@ -0,0 +1,13 @@
+function ext = extractFileExtension(filename)
+    % get extension from filename (string or char array)
+    % this function is called by save_as_file.m to decide which download method to use
+
+    filename = char(filename);
+    possibleExtensionStartIndex = strfind(filename, '.');
+    if ~isempty(possibleExtensionStartIndex)
+        extensionStartIndex = possibleExtensionStartIndex(end);
+        ext = filename(extensionStartIndex + 1:end);
+    else
+        ext = '';
+    end
+end

onc/+util/save_as_file.m

@@ -6,7 +6,7 @@
 % @param fileName  Name of the file to save
 % @param overwrite If true will overwrite files with the same name
 % @return (numeric) Result code from {0: done, -1: error, -2: fileExists}
-function endCode = save_as_file(response, filePath, fileName, varargin)
+function endCode = save_as_file(dataToWrite, filePath, fileName, varargin)
 [overwrite] = util.param(varargin, 'overwrite', false);
 
 fullPath = fileName;
@@ -25,25 +25,38 @@
     try
         matlabVersion = version('-release');
         year = str2double(matlabVersion(1:end-1));
-        if year >= 2021
-            f = fopen(fullPath, 'w','n','ISO-8859-1');
-        else
-            f = fopen(fullPath, 'w','n');
-        end
-
-        if f ~= -1
-            fwrite(f, response);
+
+        ext = util.extractFileExtension(fileName);
+
+        % if result is an image file or .xml file, use other save methods instead of fwrite. 
+        if strcmp(ext, 'png') || strcmp(ext, 'jpg')
+            imwrite(dataToWrite, fullPath);
+        elseif strcmp(ext, 'xml')
+            xmlwrite(fullPath, dataToWrite);
         else
-            endCode = -1;
-            return;
+            % open output file
+            if year >= 2021
+                f = fopen(fullPath, 'w','n','ISO-8859-1');
+            else
+                f = fopen(fullPath, 'w','n');
+            end
+
+            % write result if open file successfully
+            if f ~= -1
+                fwrite(f, char(dataToWrite));
+            else
+                endCode = -1;
+                return;
+            end
+            fclose(f);
         end
-        fclose(f);
     catch ex
         disp(ex);
         endCode = -1;
         return;
     end
 else
+    % if file exists and overwrite is false, raise exception
     throw(MException('onc:FileExistsError', 'Data product file exists in destination but overwrite is set to false'));
 end