feat: add syndication dialog for cross-posting targets

Shows a modal before publishing to let users choose which syndication
targets (e.g. Mastodon, Twitter) to cross-post to, with configurable
behaviour: always show, show when needed, or never show.

- SyndicationDialog: new Modal with per-target toggles, resolves via promise
- Publisher: accept syndicateToOverride, write mp-syndicate-to to frontmatter
- SettingsTab: add showSyndicationDialog dropdown + default targets display
- main.ts: fetch ?q=config, read frontmatter, show dialog per setting

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Publisher.ts

@@ -35,7 +35,7 @@ export class Publisher {
   }
 
   /** Publish the given file. Returns PublishResult. */
-  async publish(file: TFile): Promise<PublishResult> {
+  async publish(file: TFile, syndicateToOverride?: string[]): Promise<PublishResult> {
     const raw = await this.app.vault.read(file);
     const { frontmatter, body } = this.parseFrontmatter(raw);
 
@@ -53,7 +53,7 @@ export class Publisher {
     const linkedBody = this.resolveWikilinks(processedBody, file.path);
 
     // Build Micropub properties
-    const properties = this.buildProperties(frontmatter, linkedBody, uploadedUrls, file.basename, file.path);
+    const properties = this.buildProperties(frontmatter, linkedBody, uploadedUrls, file.basename, file.path, syndicateToOverride);
 
     let result: PublishResult;
 
@@ -69,9 +69,14 @@ export class Publisher {
       result = await this.client.createPost(properties);
     }
 
-    // Write URL back to frontmatter
-    if (result.success && result.url && this.settings.writeUrlToFrontmatter) {
-      await this.writeUrlToNote(file, raw, result.url);
+    // Write URL (and syndication targets) back to frontmatter
+    if (result.success && this.settings.writeUrlToFrontmatter) {
+      if (result.url) {
+        await this.writeUrlToNote(file, raw, result.url, syndicateToOverride);
+      } else if (syndicateToOverride !== undefined) {
+        // No URL returned but we still want to record the syndication targets
+        await this.writeSyndicateToNote(file, raw, syndicateToOverride);
+      }
     }
 
     return result;
@@ -85,6 +90,7 @@ export class Publisher {
     uploadedUrls: string[],
     basename: string,
     filePath: string,
+    syndicateToOverride?: string[],
   ): Record<string, unknown> {
     const props: Record<string, unknown> = {};
 
@@ -176,13 +182,17 @@ export class Publisher {
     }
 
     // Syndication targets
-    // Support both camelCase (mpSyndicateTo) used in existing blog posts and mp-syndicate-to
-    const syndicateTo = this.resolveArray(
-      fm["mp-syndicate-to"] ?? fm["mpSyndicateTo"],
-    );
-    const allSyndicateTo = [
-      ...new Set([...this.settings.defaultSyndicateTo, ...syndicateTo]),
-    ];
+    // When the dialog was shown, syndicateToOverride contains the user's selection
+    // and takes precedence over frontmatter + settings defaults.
+    // Support both camelCase (mpSyndicateTo) used in existing blog posts and mp-syndicate-to.
+    const allSyndicateTo = syndicateToOverride !== undefined
+      ? syndicateToOverride
+      : [
+          ...new Set([
+            ...this.settings.defaultSyndicateTo,
+            ...this.resolveArray(fm["mp-syndicate-to"] ?? fm["mpSyndicateTo"]),
+          ]),
+        ];
     if (allSyndicateTo.length > 0) {
       props["mp-syndicate-to"] = allSyndicateTo;
     }
@@ -375,6 +385,7 @@ export class Publisher {
     file: TFile,
     originalContent: string,
     url: string,
+    syndicateToOverride?: string[],
   ): Promise<void> {
     // Build all fields to write back after a successful publish
     const now = new Date();
@@ -390,6 +401,11 @@ export class Publisher {
       ["published", publishedDate],
     ];
 
+    // Record the syndication targets used so future publishes know what was sent
+    if (syndicateToOverride !== undefined) {
+      fields.push(["mp-syndicate-to", `[${syndicateToOverride.join(", ")}]`]);
+    }
+
     if (this.settings.siteUrl) {
       try {
         const hostname = new URL(this.settings.siteUrl).hostname.replace(/^www\./, "");
@@ -437,6 +453,32 @@ export class Publisher {
     await this.app.vault.modify(file, fmBlock + body);
   }
 
+  /**
+   * Write mp-syndicate-to to frontmatter without touching other fields.
+   * Used when publish succeeds but returns no URL (e.g. update responses).
+   */
+  private async writeSyndicateToNote(
+    file: TFile,
+    originalContent: string,
+    syndicateTo: string[],
+  ): Promise<void> {
+    const fmMatch = originalContent.match(
+      /^(---\r?\n[\s\S]*?\r?\n---\r?\n)([\s\S]*)$/,
+    );
+    const value = `[${syndicateTo.join(", ")}]`;
+
+    if (!fmMatch) {
+      await this.app.vault.modify(
+        file,
+        `---\nmp-syndicate-to: ${value}\n---\n` + originalContent,
+      );
+      return;
+    }
+
+    const fmBlock = this.setFrontmatterField(fmMatch[1], "mp-syndicate-to", value);
+    await this.app.vault.modify(file, fmBlock + fmMatch[2]);
+  }
+
   /**
    * Replace the value of an existing frontmatter field, or insert it before
    * the closing `---` if the field is not yet present.

src/SettingsTab.ts

@@ -110,6 +110,49 @@ export class MicropubSettingsTab extends PluginSettingTab {
           }),
       );
 
+    new Setting(containerEl)
+      .setName("Syndication dialog")
+      .setDesc(
+        "When to show the cross-posting dialog before publishing. " +
+        "'When needed' shows it only if the note has no mp-syndicate-to frontmatter.",
+      )
+      .addDropdown((drop) =>
+        drop
+          .addOption("when-needed", "When needed")
+          .addOption("always", "Always")
+          .addOption("never", "Never")
+          .setValue(this.plugin.settings.showSyndicationDialog)
+          .onChange(async (value) => {
+            this.plugin.settings.showSyndicationDialog = value as
+              | "when-needed"
+              | "always"
+              | "never";
+            await this.plugin.saveSettings();
+          }),
+      );
+
+    // Show configured defaults with a clear button
+    const defaults = this.plugin.settings.defaultSyndicateTo;
+    const defaultsSetting = new Setting(containerEl)
+      .setName("Default syndication targets")
+      .setDesc(
+        defaults.length > 0
+          ? defaults.join(", ")
+          : "None configured. Targets checked by default in the publish dialog.",
+      );
+    if (defaults.length > 0) {
+      defaultsSetting.addButton((btn) =>
+        btn
+          .setButtonText("Clear defaults")
+          .setWarning()
+          .onClick(async () => {
+            this.plugin.settings.defaultSyndicateTo = [];
+            await this.plugin.saveSettings();
+            this.display();
+          }),
+      );
+    }
+
     // ── Digital Garden ───────────────────────────────────────────────────
     containerEl.createEl("h3", { text: "Digital Garden" });
 

src/SyndicationDialog.ts

@@ -0,0 +1,89 @@
+/**
+ * SyndicationDialog.ts
+ *
+ * Modal that lets the user choose which syndication targets to cross-post to.
+ * Opens as a promise — resolves with the selected UIDs, or null if cancelled.
+ */
+
+import { App, Modal, Setting } from "obsidian";
+import type { SyndicationTarget } from "./types";
+
+export class SyndicationDialog extends Modal {
+  private selected: Set<string>;
+  private resolvePromise: ((value: string[] | null) => void) | null = null;
+  private resolved = false;
+
+  constructor(
+    app: App,
+    private readonly targets: SyndicationTarget[],
+    defaultSelected: string[],
+  ) {
+    super(app);
+    this.selected = new Set(defaultSelected.filter((uid) =>
+      targets.some((t) => t.uid === uid),
+    ));
+  }
+
+  /**
+   * Opens the dialog and waits for user selection.
+   * @returns Selected target UIDs, or null if cancelled.
+   */
+  async awaitSelection(): Promise<string[] | null> {
+    return new Promise((resolve) => {
+      this.resolvePromise = resolve;
+      this.open();
+    });
+  }
+
+  onOpen(): void {
+    const { contentEl } = this;
+    contentEl.createEl("h2", { text: "Syndication targets" });
+    contentEl.createEl("p", {
+      text: "Choose where to cross-post this note.",
+      cls: "setting-item-description",
+    });
+
+    for (const target of this.targets) {
+      new Setting(contentEl)
+        .setName(target.name)
+        .addToggle((toggle) =>
+          toggle
+            .setValue(this.selected.has(target.uid))
+            .onChange((value) => {
+              if (value) this.selected.add(target.uid);
+              else this.selected.delete(target.uid);
+            }),
+        );
+    }
+
+    new Setting(contentEl)
+      .addButton((btn) =>
+        btn
+          .setButtonText("Cancel")
+          .onClick(() => {
+            this.finish(null);
+          }),
+      )
+      .addButton((btn) =>
+        btn
+          .setButtonText("Publish")
+          .setCta()
+          .onClick(() => {
+            this.finish([...this.selected]);
+          }),
+      );
+  }
+
+  onClose(): void {
+    // Resolve as cancelled if user pressed Escape or clicked outside
+    this.finish(null);
+    this.contentEl.empty();
+  }
+
+  private finish(value: string[] | null): void {
+    if (this.resolved) return;
+    this.resolved = true;
+    this.resolvePromise?.(value);
+    this.resolvePromise = null;
+  }
+}

src/main.ts

@@ -15,10 +15,12 @@
  * Based on: https://github.com/svemagie/obsidian-microblog (MIT)
  */
 
-import { Notice, Plugin, TFile } from "obsidian";
+import { Notice, Plugin, TFile, parseYaml } from "obsidian";
 import { DEFAULT_SETTINGS, type MicropubSettings } from "./types";
 import { MicropubSettingsTab } from "./SettingsTab";
 import { Publisher } from "./Publisher";
+import { MicropubClient } from "./MicropubClient";
+import { SyndicationDialog } from "./SyndicationDialog";
 import { handleProtocolCallback } from "./IndieAuth";
 
 export default class MicropubPlugin extends Plugin {
@@ -101,11 +103,19 @@ export default class MicropubPlugin extends Plugin {
       return;
     }
 
+    // ── Syndication dialog ────────────────────────────────────────────────
+    // Determine which syndication targets to use, optionally showing a dialog.
+    const syndicateToOverride = await this.resolveSyndicationTargets(file);
+    if (syndicateToOverride === null) {
+      // User cancelled the dialog — abort publish
+      return;
+    }
+
     const notice = new Notice("Publishing…", 0 /* persist until dismissed */);
 
     try {
       const publisher = new Publisher(this.app, this.settings);
-      const result = await publisher.publish(file);
+      const result = await publisher.publish(file, syndicateToOverride);
 
       notice.hide();
 
@@ -126,6 +136,81 @@ export default class MicropubPlugin extends Plugin {
     }
   }
 
+  /**
+   * Decide whether to show the syndication dialog and return the selected targets.
+   *
+   * Returns:
+   *   string[] — targets to use as override (may be empty)
+   *   undefined — no override; Publisher will use frontmatter + settings defaults
+   *   null — user cancelled; abort publish
+   */
+  private async resolveSyndicationTargets(
+    file: TFile,
+  ): Promise<string[] | undefined | null> {
+    const dialogSetting = this.settings.showSyndicationDialog;
+
+    // "never" — skip dialog entirely, let Publisher handle targets from frontmatter + settings
+    if (dialogSetting === "never") return undefined;
+
+    // Fetch available targets from the server
+    let availableTargets: import("./types").SyndicationTarget[] = [];
+    try {
+      const client = new MicropubClient(
+        () => this.settings.micropubEndpoint,
+        () => this.settings.mediaEndpoint,
+        () => this.settings.accessToken,
+      );
+      const config = await client.fetchConfig();
+      availableTargets = config["syndicate-to"] ?? [];
+    } catch {
+      // Config fetch failed — fall back to normal publish without dialog
+      new Notice(
+        "⚠️ Could not fetch syndication targets. Publishing without dialog.",
+        4000,
+      );
+      return undefined;
+    }
+
+    // No targets on this server — skip dialog (backward compatible)
+    if (availableTargets.length === 0) return undefined;
+
+    // Read mp-syndicate-to from frontmatter
+    let fmSyndicateTo: string[] | undefined;
+    try {
+      const raw = await this.app.vault.read(file);
+      const fmMatch = raw.match(/^---\r?\n([\s\S]*?)\r?\n---\r?\n/);
+      if (fmMatch) {
+        const fm = (parseYaml(fmMatch[1]) ?? {}) as Record<string, unknown>;
+        const val = fm["mp-syndicate-to"];
+        if (val !== undefined) {
+          fmSyndicateTo = Array.isArray(val) ? val.map(String) : [String(val)];
+        }
+      }
+    } catch {
+      // Malformed frontmatter — treat as absent
+    }
+
+    // Decide whether to show dialog
+    const showDialog =
+      dialogSetting === "always" ||
+      (dialogSetting === "when-needed" && fmSyndicateTo === undefined) ||
+      (fmSyndicateTo !== undefined && fmSyndicateTo.length === 0);
+
+    if (!showDialog) {
+      // Frontmatter has values and setting is "when-needed" — skip dialog
+      return undefined;
+    }
+
+    // Pre-check: use frontmatter values if non-empty, otherwise plugin defaults
+    const defaultSelected =
+      fmSyndicateTo && fmSyndicateTo.length > 0
+        ? fmSyndicateTo
+        : this.settings.defaultSyndicateTo;
+
+    const dialog = new SyndicationDialog(this.app, availableTargets, defaultSelected);
+    return dialog.awaitSelection();
+  }
+
   // ── Settings persistence ──────────────────────────────────────────────────
 
   async loadSettings(): Promise<void> {

src/types.ts

@@ -68,6 +68,14 @@ export interface MicropubSettings {
 
   /** Visibility default for new posts: "public" | "unlisted" | "private" */
   defaultVisibility: "public" | "unlisted" | "private";
+
+  /**
+   * Controls when the syndication target dialog is shown before publishing.
+   *   "when-needed" — Show only if mp-syndicate-to is absent from frontmatter
+   *   "always"      — Show every time, even if frontmatter has targets
+   *   "never"       — Never show dialog; use defaultSyndicateTo + frontmatter
+   */
+  showSyndicationDialog: "when-needed" | "always" | "never";
 }
 
 export const DEFAULT_SETTINGS: MicropubSettings = {
@@ -83,6 +91,7 @@ export const DEFAULT_SETTINGS: MicropubSettings = {
   writeUrlToFrontmatter: true,
   mapGardenTags: true,
   defaultVisibility: "public",
+  showSyndicationDialog: "when-needed",
 };
 
 /** A syndication target as returned by Micropub config query */