Add /works/{id}/thumbnail route

package.json

@@ -13,6 +13,7 @@
     "@aws-sdk/signature-v4": "^3.130.0",
     "axios": ">=0.21.1",
     "base64-js": "^1.5.1",
+    "jsonwebtoken": "^8.5.1",
     "lz-string": "^1.4.4"
   },
   "scripts": {

src/aws/environment.js

@@ -1,3 +1,14 @@
+const jwt = require("jsonwebtoken");
+
+function apiToken() {
+  const token = {
+    displayName: ["Digital Collection API v2"],
+    iat: Math.floor(Number(new Date()) / 1000),
+  };
+
+  return jwt.sign(token, process.env.API_TOKEN_SECRET);
+}
+
 function elasticsearchEndpoint() {
   return process.env.ELASTICSEARCH_ENDPOINT;
 }
@@ -12,4 +23,4 @@ function region() {
   return process.env.AWS_REGION || "us-east-1";
 }
 
-module.exports = { elasticsearchEndpoint, prefix, region };
+module.exports = { apiToken, elasticsearchEndpoint, prefix, region };

src/handlers/get-work-thumbnail.js

@@ -0,0 +1,58 @@
+const { apiToken } = require("../aws/environment");
+const axios = require("axios").default;
+const middleware = require("./middleware");
+const { getWork } = require("../api/opensearch");
+const opensearchResponse = require("../api/response/opensearch");
+
+function getAxiosResponse(url, config) {
+  return new Promise((resolve) => {
+    axios
+      .get(url, config)
+      .then((response) => resolve(response))
+      .catch((error) => resolve(error.response));
+  });
+}
+
+/**
+ * A simple function to proxy a Work's thumbnail from the IIIF server
+ */
+exports.handler = async (event) => {
+  event = middleware(event);
+  const id = event.pathParameters.id;
+  const esResponse = await getWork(id);
+  if (esResponse.statusCode != 200) {
+    return opensearchResponse.transform(esResponse);
+  }
+
+  const body = JSON.parse(esResponse.body);
+  const thumbnail = body?._source?.thumbnail;
+
+  if (thumbnail === undefined) {
+    return {
+      statusCode: 404,
+      body: "Not Found",
+    };
+  }
+
+  const { status, headers, data } = await getAxiosResponse(thumbnail, {
+    headers: { Authorization: `Bearer ${apiToken()}` },
+    responseType: "arraybuffer",
+  });
+
+  if (status != 200) {
+    return {
+      statusCode: status,
+      body: data.toString(),
+      headers: headers,
+    };
+  }
+
+  return {
+    statusCode: status,
+    isBase64Encoded: true,
+    body: data.toString("base64"),
+    headers: {
+      "content-type": headers["content-type"],
+    },
+  };
+};