From 609ee6cd3c79e8b5ad9c75fed40b57cfd650a307 Mon Sep 17 00:00:00 2001
From: lmdev <138343225+lmdevv@users.noreply.github.com>
Date: Fri, 4 Sep 2026 00:32:38 -0400
Subject: [PATCH] api/loom: add transcript-only downloads

---
 api/README.md                          |  4 +-
 api/src/processing/helpers/captions.js | 52 ++++++++++++++++----------
 api/src/processing/match.js            |  3 ++
 api/src/processing/service-config.js   |  2 +-
 api/src/processing/services/loom.js    | 38 +++++++++++++++++--
 api/src/util/tests/loom.json           | 12 ++++++
 6 files changed, 84 insertions(+), 27 deletions(-)

diff --git a/api/README.md b/api/README.md
index 4bc2caf6..3fb049af 100644
--- a/api/README.md
+++ b/api/README.md
@@ -22,7 +22,7 @@ if the desired service isn't supported yet, feel free to create an appropriate i
 | dailymotion       | ✅            | ✅         | ✅         | ❌              | ✅         | ✅              |
 | instagram         | ✅            | ✅         | ✅         | ❌              | ➖         | ➖              |
 | facebook          | ✅            | ❌         | ✅         | ❌              | ➖         | ➖              |
-| loom              | ✅            | ❌         | ✅         | ❌              | ✅         | ➖              |
+| loom              | ✅            | ❌         | ✅         | ✅              | ✅         | ➖              |
 | newgrounds        | ✅            | ✅         | ✅         | ❌              | ✅         | ✅              |
 | ok.ru             | ✅            | ❌         | ✅         | ❌              | ✅         | ✅              |
 | pinterest         | ✅            | ✅         | ✅         | ❌              | ➖         | ➖              |
@@ -45,7 +45,7 @@ if the desired service isn't supported yet, feel free to create an appropriate i
 | ➖      | unreasonable/impossible |
 | ❌      | not supported           |
 
-standalone transcript downloads are supported for youtube with `downloadMode: "captions"`.
+standalone transcript downloads are supported for marked services with `downloadMode: "captions"`.
 
 ### additional notes or features (per service)
 | service    | notes or features                                                                                                    |
diff --git a/api/src/processing/helpers/captions.js b/api/src/processing/helpers/captions.js
index 7109bcac..94edef87 100644
--- a/api/src/processing/helpers/captions.js
+++ b/api/src/processing/helpers/captions.js
@@ -1,5 +1,14 @@
 const normalizedLanguage = language => language?.toLowerCase().replace("_", "-");
 
+export const matchesCaptionLanguage = (language, requested) => {
+    if (!requested || !language) return true;
+
+    const normalized = normalizedLanguage(language);
+    const normalizedRequested = normalizedLanguage(requested);
+    return normalized === normalizedRequested
+        || normalized?.split("-")[0] === normalizedRequested?.split("-")[0];
+};
+
 export const createCaptionResponse = ({
     url,
     format,
@@ -10,26 +19,29 @@ export const createCaptionResponse = ({
     author,
     source,
     headers,
-}) => ({
-    type: "captions",
-    isCaptionOnly: true,
-    urls: url,
-    headers,
-    captionFormat: format,
-    captionLanguage: language,
-    filenameAttributes: {
-        service,
-        id,
-        title: title || `${service}_${id}`,
-        author,
-    },
-    captionMetadata: {
-        title,
-        author,
-        language,
-        source,
-    },
-});
+}) => {
+    const resolvedTitle = title || `${service}_${id}`;
+    return {
+        type: "captions",
+        isCaptionOnly: true,
+        urls: url,
+        headers,
+        captionFormat: format,
+        captionLanguage: language || "unknown",
+        filenameAttributes: {
+            service,
+            id,
+            title: resolvedTitle,
+            author,
+        },
+        captionMetadata: {
+            title: resolvedTitle,
+            author,
+            language,
+            source,
+        },
+    };
+};
 
 export const selectCaptionTrack = (tracks, subtitleLang, allowAutomatic = false) => {
     const allowed = tracks.filter(track => allowAutomatic || track.kind !== "asr");
diff --git a/api/src/processing/match.js b/api/src/processing/match.js
index c3373cde..481986c5 100644
--- a/api/src/processing/match.js
+++ b/api/src/processing/match.js
@@ -252,6 +252,9 @@ export default async function({ host, patternMatch, params, authType }) {
                 r = await loom({
                     id: patternMatch.id,
                     subtitleLang,
+                    isCaptionOnly,
+                    captionLanguage: params.captionLanguage || subtitleLang,
+                    captionFormat: params.captionFormat,
                 });
                 break;
 
diff --git a/api/src/processing/service-config.js b/api/src/processing/service-config.js
index fbcc26d2..f5206ad7 100644
--- a/api/src/processing/service-config.js
+++ b/api/src/processing/service-config.js
@@ -1,7 +1,7 @@
 import UrlPattern from "url-pattern";
 
 export const audioIgnore = new Set(["vk", "ok", "loom"]);
-export const captionOnlyServices = new Set(["youtube"]);
+export const captionOnlyServices = new Set(["loom", "youtube"]);
 export const hlsExceptions = new Set(["dailymotion", "vimeo", "rutube", "bsky", "youtube"]);
 
 export const services = {
diff --git a/api/src/processing/services/loom.js b/api/src/processing/services/loom.js
index 64382108..47272a17 100644
--- a/api/src/processing/services/loom.js
+++ b/api/src/processing/services/loom.js
@@ -1,4 +1,8 @@
 import { genericUserAgent } from "../../config.js";
+import {
+    createCaptionResponse,
+    matchesCaptionLanguage,
+} from "../helpers/captions.js";
 
 const craftHeaders = id => ({
     "user-agent": genericUserAgent,
@@ -80,12 +84,38 @@ async function getTranscript(id) {
     .then(r => r.status === 200 && r.json())
     .catch(() => {});
 
-    if (gql?.data?.fetchVideoTranscript?.captions_source_url?.includes('.vtt?')) {
-        return gql.data.fetchVideoTranscript.captions_source_url;
+    const transcript = gql?.data?.fetchVideoTranscript;
+    if (transcript?.captions_source_url?.includes('.vtt?')) {
+        return {
+            url: transcript.captions_source_url,
+            language: transcript.language,
+        };
     }
 }
 
-export default async function({ id, subtitleLang }) {
+export default async function({
+    id,
+    subtitleLang,
+    isCaptionOnly,
+    captionLanguage,
+    captionFormat,
+}) {
+    if (isCaptionOnly) {
+        const transcript = await getTranscript(id);
+        if (!transcript || !matchesCaptionLanguage(transcript.language, captionLanguage)) {
+            return { error: "fetch.empty" };
+        }
+
+        return createCaptionResponse({
+            url: transcript.url,
+            format: captionFormat,
+            language: transcript.language,
+            service: "loom",
+            id,
+            source: `https://www.loom.com/share/${id}`,
+        });
+    }
+
     let url = await fromTranscodedURL(id);
     url ??= await fromRawURL(id);
 
@@ -96,7 +126,7 @@ export default async function({ id, subtitleLang }) {
     let subtitles;
     if (subtitleLang) {
         const transcript = await getTranscript(id);
-        if (transcript) subtitles = transcript;
+        if (transcript) subtitles = transcript.url;
     }
 
     return {
diff --git a/api/src/util/tests/loom.json b/api/src/util/tests/loom.json
index 0ebb4580..4dd38479 100644
--- a/api/src/util/tests/loom.json
+++ b/api/src/util/tests/loom.json
@@ -30,6 +30,18 @@
             "status": "error"
         }
     },
+    {
+        "name": "standalone transcript",
+        "url": "https://www.loom.com/share/aa3d8b08bee74d05af5b42989e9f33e9",
+        "params": {
+            "downloadMode": "captions",
+            "captionFormat": "txt"
+        },
+        "expected": {
+            "code": 200,
+            "status": "tunnel"
+        }
+    },
     {
         "name": "video with no transcodedUrl",
         "url": "https://www.loom.com/share/aa3d8b08bee74d05af5b42989e9f33e9",