docs: update parser plugin readme and add example danbooru parser

plugins/example_parser_danbooru.js

@@ -0,0 +1,138 @@
+// Danbooru post parser for SaveAnyBot
+// request https://danbooru.donmai.us/posts/{id}.json and parse the response
+
+const metadata = {
+    name: "Danbooru Post Parser",
+    version: "1.0.0",
+    description: "Parse Danbooru post links via official JSON API",
+    author: "Krau",
+};
+
+// some utils
+const danbooruSourceURLRegexp = /danbooru\.donmai\.us\/(posts|post\/show)\/(\d+)/;
+function getPostID(url) {
+    const m = url.match(danbooruSourceURLRegexp);
+    return m ? m[2] : "";
+}
+function normalizePostURL(id) {
+    return `https://danbooru.donmai.us/posts/${id}`;
+}
+function apiURLFor(id) {
+    return `https://danbooru.donmai.us/posts/${id}.json`;
+}
+
+
+function basenameFromURL(u) {
+    try {
+        const q = u.split("?")[0];
+        const parts = q.split("/");
+        const name = parts[parts.length - 1] || "";
+        return name || "file";
+    } catch (_) {
+        return "file";
+    }
+}
+function extFromFilename(name) {
+    const idx = name.lastIndexOf(".");
+    if (idx < 0) return "";
+    return name.slice(idx + 1).toLowerCase();
+}
+function mimeFromExt(ext) {
+    switch (ext) {
+        case "jpg":
+        case "jpeg":
+            return "image/jpeg";
+        case "png":
+            return "image/png";
+        case "gif":
+            return "image/gif";
+        default:
+            return "";
+    }
+}
+
+// implement canHandle and parse
+const canHandle = function (url) {
+    return danbooruSourceURLRegexp.test(url);
+};
+
+const parse = function (sourceURL) {
+    const id = getPostID(sourceURL);
+    if (!id) {
+        throw new Error("invalid danbooru post url");
+    }
+
+    const normURL = normalizePostURL(id);
+
+    const apiURL = apiURLFor(id);
+    console.log("Danbooru requesting", "url", apiURL);
+    // You can use ghttp.getJSON to fetch and parse JSON in one step.
+    // While the ghttp.get can be used to fetch raw response.
+    const data = ghttp.getJSON(apiURL);
+
+    if (data && data.error) {
+        throw new Error(data.message || "danbooru returned error");
+    }
+
+    const fileURL = data.file_url || "";
+    const largeURL = data.large_file_url || "";
+    const width = data.image_width || 0;
+    const height = data.image_height || 0;
+
+    if (!fileURL && !largeURL) {
+        throw new Error("danbooru response has no file_url / large_file_url");
+    }
+
+    const resources = [];
+    if (fileURL) {
+        const name = basenameFromURL(fileURL);
+        const ext = extFromFilename(name);
+        resources.push({
+            url: fileURL,
+            filename: name,
+            mime_type: mimeFromExt(ext),
+            extension: ext,
+            size: 0,
+            hash: {},
+            headers: {},
+            extra: { width, height, kind: "original" },
+        });
+    }
+    if (largeURL && largeURL !== fileURL) {
+        const name = basenameFromURL(largeURL);
+        const ext = extFromFilename(name);
+        resources.push({
+            url: largeURL,
+            filename: name,
+            mime_type: mimeFromExt(ext),
+            extension: ext,
+            size: 0,
+            hash: {},
+            headers: {},
+            extra: { width, height, kind: "large" },
+        });
+    }
+
+    const tags = (data.tag_string ? String(data.tag_string) : "")
+        .split(" ")
+        .filter(Boolean);
+
+    const item = {
+        site: "Danbooru",
+        url: normURL,
+        title: `Danbooru/${data.id || id}`,
+        author: "Danbooru",
+        description: "",
+        tags: tags,
+        resources: resources,
+        extra: {},
+    };
+
+    return item;
+};
+
+registerParser({
+    metadata,
+    canHandle,
+    parse,
+});