From ae64489b0dbc9a73a9f48aa42b22b77e0b168d19 Mon Sep 17 00:00:00 2001
From: Daniel McCartney <dmccartney@gmail.com>
Date: Tue, 5 Sep 2023 16:52:45 -0400
Subject: [PATCH] fix: normalize reaction encoding, support legacy form

---
 .../src/Reaction.test.ts                      | 40 +++++++++++++++++
 .../content-type-reaction/src/Reaction.ts     | 45 ++++++++++++-------
 packages/content-type-reaction/src/index.ts   |  2 +-
 3 files changed, 69 insertions(+), 18 deletions(-)

diff --git a/packages/content-type-reaction/src/Reaction.test.ts b/packages/content-type-reaction/src/Reaction.test.ts
index 676fb0f..e0c52a4 100644
--- a/packages/content-type-reaction/src/Reaction.test.ts
+++ b/packages/content-type-reaction/src/Reaction.test.ts
@@ -11,6 +11,46 @@ describe("ReactionContentType", () => {
     expect(ContentTypeReaction.versionMinor).toBe(0);
   });
 
+  it("supports canonical and legacy form", async () => {
+    let codec = new ReactionCodec();
+
+    // This is how clients send reactions now.
+    let canonicalEncoded = {
+      type: ContentTypeReaction,
+      content: new TextEncoder().encode(
+        JSON.stringify({
+          action: "added",
+          content: "smile",
+          reference: "abc123",
+          schema: "shortcode",
+        }),
+      ),
+    };
+
+    // Previously, some clients sent reactions like this.
+    // So we test here to make sure we can still decode them.
+    let legacyEncoded = {
+      type: ContentTypeReaction,
+      parameters: {
+        action: "added",
+        reference: "abc123",
+        schema: "shortcode",
+      },
+      content: new TextEncoder().encode("smile"),
+    };
+
+    let canonical = codec.decode(canonicalEncoded as any);
+    let legacy = codec.decode(legacyEncoded as any);
+    expect(canonical.action).toBe("added");
+    expect(legacy.action).toBe("added");
+    expect(canonical.content).toBe("smile");
+    expect(legacy.content).toBe("smile");
+    expect(canonical.reference).toBe("abc123");
+    expect(legacy.reference).toBe("abc123");
+    expect(canonical.schema).toBe("shortcode");
+    expect(legacy.schema).toBe("shortcode");
+  });
+
   it("can send a reaction", async () => {
     const aliceWallet = Wallet.createRandom();
     const aliceClient = await Client.create(aliceWallet, { env: "local" });
diff --git a/packages/content-type-reaction/src/Reaction.ts b/packages/content-type-reaction/src/Reaction.ts
index 27abe92..f81930d 100644
--- a/packages/content-type-reaction/src/Reaction.ts
+++ b/packages/content-type-reaction/src/Reaction.ts
@@ -27,9 +27,9 @@ export type Reaction = {
   schema: "unicode" | "shortcode" | "custom";
 };
 
-export type ReactionParameters = Pick<
-  Reaction,
-  "action" | "reference" | "schema"
+type LegacyReactionParameters = Pick<
+    Reaction,
+    "action" | "reference" | "schema"
 > & {
   encoding: "UTF-8";
 };
@@ -39,29 +39,40 @@ export class ReactionCodec implements ContentCodec<Reaction> {
     return ContentTypeReaction;
   }
 
-  encode(content: Reaction): EncodedContent<ReactionParameters> {
+  encode(reaction: Reaction): EncodedContent {
+    const { action, reference, schema, content } = reaction;
     return {
       type: ContentTypeReaction,
-      parameters: {
-        encoding: "UTF-8",
-        action: content.action,
-        reference: content.reference,
-        schema: content.schema,
-      },
-      content: new TextEncoder().encode(content.content),
+      parameters: {},
+      content: new TextEncoder().encode(
+        JSON.stringify({ action, reference, schema, content }),
+      ),
     };
   }
 
-  decode(content: EncodedContent<ReactionParameters>): Reaction {
-    const { encoding } = content.parameters;
+  decode(content: EncodedContent): Reaction {
+    let text = new TextDecoder().decode(content.content);
+
+    // First try to decode it in the canonical form.
+    try {
+      const reaction = JSON.parse(text);
+      const { action, reference, schema, content } = reaction;
+      return { action, reference, schema, content };
+    } catch (e) {
+      // ignore, fall through to legacy decoding
+    }
+
+    // If that fails, try to decode it in the legacy form.
+    let parameters = content.parameters as LegacyReactionParameters;
+    const { encoding } = parameters;
     if (encoding && encoding !== "UTF-8") {
       throw new Error(`unrecognized encoding ${encoding as string}`);
     }
     return {
-      action: content.parameters.action,
-      reference: content.parameters.reference,
-      schema: content.parameters.schema,
-      content: new TextDecoder().decode(content.content),
+      action: parameters.action,
+      reference: parameters.reference,
+      schema: parameters.schema,
+      content: text,
     };
   }
 }
diff --git a/packages/content-type-reaction/src/index.ts b/packages/content-type-reaction/src/index.ts
index 1b80abf..edc7e20 100644
--- a/packages/content-type-reaction/src/index.ts
+++ b/packages/content-type-reaction/src/index.ts
@@ -1,2 +1,2 @@
 export { ReactionCodec, ContentTypeReaction } from "./Reaction";
-export type { Reaction, ReactionParameters } from "./Reaction";
+export type { Reaction } from "./Reaction";