Plantuml plugin not working on SB+ on my work laptop

wouter · June 6, 2026, 7:42pm

My work laptop is running W11. I have the latest version of SB+. I started a new space and installed LogeshG5 plantuml plugin under Libraries via 'Install from URI'.
A plantuml block get rendered as Error: Offline.
When I run a local SB server on the same space, it gets rendered fine on Edge browser.

I thought this could be a firewall issue. The silverbullet-app.exe had no rules, so I added rules to allow traffic on domain, private and public networks. To no avail...

I figure it must be something limiting the SB+ executable, since it works on Edge. Also tried running SB+ as (local) admin, but that makes no difference.

Somebody here has more ideas towards a solution? Or propose some steps for troubleshooting?

i_am_dangry · June 7, 2026, 10:03pm

I have a similar issue with the Excalidraw plugin made by the same dev. Works fine in browser/PWA but not in SB+, it errors with "widget not found" or something similar. Did raise an issue on their GH, but wondering if there is something in SB+ that causes a problem.

wouter · June 12, 2026, 6:59pm

I had a look in the developer tools. On the console tab, filter for 'plant' I see following:

VM27:18 [Client] Activated plug plantuml
VM27:18 [Client] Booting up worker from /.fs/plantuml.plug.js
plantuml.plug.js:1 silverbullet-plantuml: requesting https://plantuml.com/plantuml/svg/SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKiX8pSd9LwXKJyp9uN98pKi1AW40
:17754/.proxy/plantuml.com/plantuml/svg/SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKiX8pSd9LwXKJyp9uN98pKi1AW40:1  Failed to load resource: the server responded with a status of 500 (Internal Server Error)
plantuml.plug.js:1 PUML generation failed Error: Offline
    at plantuml.plug.js:1:55554
    at plantuml.plug.js:1:55602
ar @ plantuml.plug.js:1
logger.ts:43 [index plug] [index] Indexing file plantuml.plug.js

So the link to the plantuml server on line 3 renders just fine. The link on line 4 (starting with :17754) shows an internal server error:

error sending request for url (https://plantuml.com/plantuml/svg/SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKiX8pSd9LwXKJyp9uN98pKi1AW40)

I do not see this step if I run the space through a local server.

Where would this problem arise? Is it in some specifics regarding SB+, or is it something in the plantuml plug?

LogeshG5 · June 13, 2026, 3:40am

@zef Is fetch expected to work with Silverbullet+

const response = await fetch(url);

plantuml.plug.js:1 silverbullet-plantuml: requesting https://plantuml.com/plantuml/svg/SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKiX8pSd9LwXKJyp9uN98pKi1AW40
:17754/.proxy/plantuml.com/plantuml/svg/SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKiX8pSd9LwXKJyp9uN98pKi1AW40:1  Failed to load resource: the server responded with a status of 500 (Internal Server Error)
plantuml.plug.js:1 PUML generation failed Error: Offline

github.com/LogeshG5/silverbullet-plantuml

plantuml.ts

main


      
          }
          
          export async function pumlserver(serverurl: string, uml: string) {
            try {
              let encoded = plantumlEncoder.encode(uml);
              let sep = "/";
              if (serverurl.endsWith("/"))
                sep = "";
              let url = serverurl + sep + 'svg/' + encoded;
              console.log("silverbullet-plantuml: requesting", url);
              const response = await fetch(url);
              if (!response.ok) {
                throw new Error(`HTTP error! status: ${response.status}`);
              }
              const data = await response.text();
              return data;
            } catch (error) {
              console.error("PUML generation failed", error);
              return error;
            }
          }