diff --git a/bin/server b/bin/server
index f8ce8b9..9071a88 100755
--- a/bin/server
+++ b/bin/server
@@ -47,7 +47,7 @@ async function init() {
 
         return logger.info('Server running at %s', server.info.uri);
     } catch (err) {
-        logger.error(err);
+        logger.error(err.toString());
 
         return process.exit(1);
     }
diff --git a/config/default.yaml b/config/default.yaml
index ae5df1d..cb79764 100644
--- a/config/default.yaml
+++ b/config/default.yaml
@@ -62,6 +62,8 @@ strategy:
         accessKeyId: null
         # Amazon secret access key
         secretAccessKey: null
+        # Amazon Session Token from federated credentials
+        sessionToken: null
         # Amazon S3 region
         region: YOUR-REGION
         # Amazon S3 bucket that you have write access to
diff --git a/helpers/aws.js b/helpers/aws.js
index 7389148..3243ff7 100644
--- a/helpers/aws.js
+++ b/helpers/aws.js
@@ -19,6 +19,7 @@ class AwsClient {
      * @param  {String}    config.segment            S3 segment
      * @param  {Integer}   config.partSize           aws-sdk upload option
      * @param  {Integer}   config.httpTimeout        HTTP timeout in ms
+     * @param  {String }   config.sessionToken       Session token for federated AWS login
      */
     constructor(config) {
         const options = {
@@ -31,6 +32,10 @@ class AwsClient {
             }
         };
 
+        if (config.sessionToken) {
+            options.sessionToken = config.sessionToken;
+        }
+
         if (config.endpoint) {
             options.endpoint = config.endpoint;
         }
diff --git a/helpers/mime.js b/helpers/mime.js
index cbc9179..56196b3 100644
--- a/helpers/mime.js
+++ b/helpers/mime.js
@@ -2,13 +2,19 @@
 
 const mime = require('mime-types');
 
+const FORCE_EXTENSION_MAPPING = {
+    yidf: 'txt',
+    state: 'txt',
+    diff: 'txt'
+};
+
 /**
  * getMimeFromFileExtension
  * @param  {String} fileExtension  File extension (e.g. css, txt, html)
  * @return {String} text/html
  */
 function getMimeFromFileExtension(fileExtension) {
-    return mime.lookup(fileExtension) || '';
+    return mime.lookup(FORCE_EXTENSION_MAPPING[fileExtension] || fileExtension) || '';
 }
 
 const knownMimes = ['text/css', 'text/javascript', 'image/png', 'image/jpeg', 'application/json',
diff --git a/plugins/auth.js b/plugins/auth.js
index 8281b34..ed4cf04 100644
--- a/plugins/auth.js
+++ b/plugins/auth.js
@@ -36,7 +36,7 @@ exports.plugin = {
             key: pluginOptions.jwtPublicKey,
             verifyOptions: {
                 algorithms: ['RS256'],
-                maxAge: '12h'
+                maxAge: '13h'
             },
             // This function is run once the Token has been decoded with signature
             validate
diff --git a/plugins/builds.js b/plugins/builds.js
index 8ad81b3..2ff963f 100644
--- a/plugins/builds.js
+++ b/plugins/builds.js
@@ -58,6 +58,7 @@ exports.plugin = {
 
                 let value;
                 let response;
+                let isStreamOutput = false;
 
                 // for old json files, the value is hidden in an object, we cannot stream it directly
                 if (usingS3) {
@@ -65,6 +66,7 @@ exports.plugin = {
                         value = await awsClient.getDownloadStream({ cacheKey: id });
                         response = h.response(value);
                         response.headers['content-type'] = 'application/octet-stream';
+                        isStreamOutput = true;
                     } catch (err) {
                         request.log([id, 'error'], `Failed to stream the cache: ${err}`);
                         throw err;
@@ -104,7 +106,14 @@ exports.plugin = {
                         `attachment; filename="${encodeURI(fileName)}"`;
                 } else if (request.query.type === 'preview') {
                     if (displayableMimes.includes(mime)) {
-                        const $ = cheerio.load(Buffer.from(value));
+                        let htmlContent;
+
+                        if (isStreamOutput) {
+                            htmlContent = await streamToBuffer(value);
+                        } else {
+                            htmlContent = Buffer.from(value);
+                        }
+                        const $ = cheerio.load(htmlContent);
                         const scriptNode = `<script>${iframeScript}</script>`;
 
                         // inject postMessage into code
diff --git a/test/plugins/builds.test.js b/test/plugins/builds.test.js
index 72d735b..4353bc0 100644
--- a/test/plugins/builds.test.js
+++ b/test/plugins/builds.test.js
@@ -14,6 +14,7 @@ sinon.assert.expose(assert, { prefix: '' });
 describe('builds plugin test', () => {
     let plugin;
     let server;
+    let configMock;
 
     before(() => {
         mockery.enable({
@@ -23,6 +24,13 @@ describe('builds plugin test', () => {
     });
 
     beforeEach(() => {
+        configMock = {
+            get: sinon.stub().returns({
+                plugin: 'memory',
+                s3: {}
+            })
+        };
+        mockery.registerMock('config', configMock);
         // eslint-disable-next-line global-require
         plugin = require('../../plugins/builds');