Plugin to Upload a File

[Leirbag Assuab]

Hi Experts!

I'm developing an add-on for JIRA that needs a file to be uploaded. The file contains rules in JSON format that define the behaviour of the add-on.
I've defined a multipart-config servlet and a multipart/form-data form in admin page. But I can't retrieve any part with getPart method at servlet side, it seems to arrive "empty", like no form was defined.

These are some pieces of my code:

upload rules template (vm):

...
<form id="upload-rules" class="aui" method="POST" enctype="multipart/form-data">
 <input type="hidden" id="uploading" name="uploading" value="y">
 <input type="hidden" id="test" name="test" value="y">

<div class="field-group">
 <label for="file">Rules config file<span class="aui-icon icon-required">(required)</span></label>
 <input type="file" id="file" name="file" class="file">
 </div>

<div class="field-group">
 <input type="submit" value="Upload" class="button" name="upload" id="upload">
 <a href="$baseURL/plugins/servlet/upm">Cancel</a> 
 </div>

</form>
...

RulesServlet.java:

...
@Named("RulesServlet")
@MultipartConfig
public class RulesServlet extends HttpServlet
{
 ...
 
 @Override
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
 LOG.debug("doPost method called.");
 
 //Only admin users are admitted
 if (!isAdminUser(request)) {
 redirectToLogin(request, response);
 return;
 }

try {
 LOG.debug("Updating rules...");
 
 LOG.debug("Request content type: " + request.getContentType());
 LOG.debug("Request parameterMap size: " + request.getParameterMap().size());
 LOG.debug("Request parts size: " + request.getParts().size());
 
 Part filePart = request.getPart("file"); // Retrieves <input type="file" name="file">
 String fileName = Paths.get(getSubmittedFileName(filePart)).getFileName().toString(); // MSIE fix.
 InputStream fileContent = filePart.getInputStream();

...stuff to get rules from file...

response.setContentType(CONTENT_TYPE);
 renderer.render(UPLOAD_TEMPLATE, context, response.getWriter());

} catch (Exception e) {
 LOG.error("Error creating escalate rules.", e);
 throw new ServletException(e);
 }

} 
 
 private static String getSubmittedFileName(Part part) {
 for (String cd : part.getHeader("content-disposition").split(";")) {
 if (cd.trim().startsWith("filename")) {
 String fileName = cd.substring(cd.indexOf('=') + 1).trim().replace("\"", "");
 return fileName.substring(fileName.lastIndexOf('/') + 1).substring(fileName.lastIndexOf('\\') + 1); // MSIE fix.
 }
 }
 return null;
 } 
 
}
...

atlassian-plugin.xml:

...
<servlet key="mim-autoescalate-upload-rules-servlet" i18n-name-key="mim-autoescalate-rules-upload-servlet.name" 
 class="cat.palma.jira.escalate.ui.RulesServlet" name="MIM Autoescalate Plugin Upload Rules Servlet">
 <description key="mim-autoescalate-rules-upload-servlet.description">The rules upload servlet to populate the MIM Autoescalate Plugin rule table</description>
 <url-pattern>/mimautoescalateplugin/rules</url-pattern>
</servlet>
...
<web-item key="mim-autoescalate-link-upload-rules" i18n-name-key="mim-autoescalate-link-upload-rules.name"
 name="MIM Autoescalate Plugin Setup Rules Link" section="admin_plugins_menu/mim-autoescalate-section" weight="1010">
 <description key="mim-autoescalate-link-upload-rules.description">The Setup Page Link for escalate rules of MIM Autoescalate Plugin</description>
 <label key="mim-autoescalate-link-upload-rules.label"></label>
 <link linkId="mim-autoescalate-link-upload-rules-link">/plugins/servlet/mimautoescalateplugin/rules?op=preupload</link>
</web-item>
...

pom.xml:

...
<dependency>
 <groupId>javax.servlet</groupId>
 <artifactId>servlet-api</artifactId>
 <version>2.4</version>
 <scope>provided</scope>
</dependency>
...
<properties>
 <jira.version>7.7.1</jira.version>
 <amps.version>6.3.15</amps.version>
 <plugin.testrunner.version>1.2.3</plugin.testrunner.version>
 <atlassian.spring.scanner.version>1.2.13</atlassian.spring.scanner.version>
 <maven.compiler.source>1.8</maven.compiler.source>
 <maven.compiler.target>1.8</maven.compiler.target>
 <atlassian.template.renderer.version>2.0.0</atlassian.template.renderer.version>
 <activeobjects.version>1.5.0</activeobjects.version>
 <spring.version>4.2.5.RELEASE</spring.version>
 <gson.version>2.3.1</gson.version>
...
</properties>
...

After picking up a file and press upload button, following messages from servlet debug appear in log:

[INFO] [talledLocalContainer] 2018-05-17 09:00:55,820 DEBUG admin [c.p.j.escalate.ui.RulesServlet] doPost method called.
[INFO] [talledLocalContainer] 2018-05-17 09:00:55,821 DEBUG admin [c.p.j.escalate.ui.RulesServlet] User performing action admin.
[INFO] [talledLocalContainer] 2018-05-17 09:00:55,822 DEBUG admin [c.p.j.escalate.ui.RulesServlet] Updating rules...
[INFO] [talledLocalContainer] 2018-05-17 09:00:55,822 DEBUG admin [c.p.j.escalate.ui.RulesServlet] Request content type: multipart/form-data; boundary=----WebKitFormBoundaryxRnbEsLcgjpzyKWn
[INFO] [talledLocalContainer] 2018-05-17 09:00:55,822 DEBUG admin [c.p.j.escalate.ui.RulesServlet] Request parameterMap size: 1
[INFO] [talledLocalContainer] 2018-05-17 09:00:55,823 DEBUG admin [c.p.j.escalate.ui.RulesServlet] Request parts size: 0
[INFO] [talledLocalContainer] 2018-05-17 09:00:55,823 ERROR admin [c.p.j.escalate.ui.RulesServlet] Error creating escalate rules.
[INFO] [talledLocalContainer] java.lang.NullPointerException

ParameterMap contains only "op" parameter from link (".../plugins/servlet/mimautoescalateplugin/rules?op=preupload").
request.getParts().size() is 0, so request.getPart("file") returns null and no file is uploaded. Seems like no form was defined.

Does anyone has any idea about what's going on or where error is?

Thanks in advance!!
__________
Leirbag A.