a very rudimentary thumbnail service, work for #10

oduwsdl · Jul 16, 2018 · fe0c9014e283f9d52d026a802e698781ca2a0f62 · fe0c901
1 parent d8fbfc0
commit fe0c9014e283f9d52d026a802e698781ca2a0f62
Unified Split

Showing with 363 additions and 2 deletions.

+1 −0 .gitignore

+3 −0 config/default.py

BIN example.png

+50 −2 mementoembed/services/product.py

+9 −0 mementoembed/static/js/create_screenshot.js

+300 −0 package-lock.json
diff --git a/.gitignore b/.gitignore
@@ -9,3 +9,4 @@ dist
 .web_cache
 *.sqlite
 *.bak
+node_modules
diff --git a/config/default.py b/config/default.py
@@ -1,3 +1,6 @@
 CACHEMODEL = 'SQLite'
 LOGLEVEL = "DEBUG"
 REQUEST_TIMEOUT = 15
+ENABLE_THUMBNAILS = "Yes"
+THUMBNAIL_SCRIPT_PATH = "mementoembed/static/js/create_screenshot.js"
+THUMBNAIL_WORKING_FOLDER = "/tmp/mementoembed/thumbnails"
diff --git a/example.png b/example.png
diff --git a/mementoembed/services/product.py b/mementoembed/services/product.py
@@ -1,10 +1,14 @@
+import os
 import logging
 import json
+import subprocess
+import traceback
+import hashlib

 import htmlmin
 import requests_cache

-from flask import render_template, request, Blueprint, current_app
+from flask import render_template, request, Blueprint, current_app, make_response

 from mementoembed.mementosurrogate import MementoSurrogate
 from mementoembed.cachesession import CacheSession
@@ -69,8 +73,52 @@ def thumbnail_endpoint(subpath):

    try:

+        # TODO: test that subpath is actually a memento
+
        if current_app.config['ENABLE_THUMBNAILS'] == "Yes":
-            return "The thumbnail service is not yet available", 500
+
+            if os.path.isdir(current_app.config['THUMBNAIL_WORKING_FOLDER']):
+                urim = subpath
+                os.environ['URIM'] = urim
+                m = hashlib.sha256()
+                m.update(urim.encode('utf8'))
+                thumbfile = m.hexdigest()
+                thumbfile = "{}/{}.png".format(current_app.config['THUMBNAIL_WORKING_FOLDER'], m.hexdigest())
+
+                os.environ['THUMBNAIL_OUTPUTFILE'] = thumbfile
+
+                p = subprocess.Popen(["node", current_app.config['THUMBNAIL_SCRIPT_PATH']])
+
+                try:
+                    p.wait(timeout=30)
+
+                    with open(thumbfile, 'rb') as f:
+                        data = f.read()
+
+                    response = make_response(data)
+                    response.headers['Content-Type'] = 'image/png'
+
+                    return response, 200
+
+                except TimeoutError:
+                    module_logger.exception("Thumbnail script failed to return after 30 seconds")
+                    
+                    output = {
+                        "error": "a thumbnail failed to generated in 30 seconds",
+                        "error details": repr(traceback.format_exc())
+                    }
+                    return json.dumps(output), 500
+
+            else:
+                msg = "Thumbnail folder {} does not exist".format(current_app.config['THUMBNAIL_WORKING_FOLDER'])
+                module_logger.exception(msg)
+                    
+                output = {
+                    "error": msg,
+                    "error details": repr(traceback.format_exc())
+                }
+                return json.dumps(output), 500
+            
        else:
            return "The thumbnail service has been disabled by the system administrator", 200

diff --git a/mementoembed/static/js/create_screenshot.js b/mementoembed/static/js/create_screenshot.js
@@ -0,0 +1,9 @@
+const puppeteer = require('puppeteer');
+
+(async () => {
+  const browser = await puppeteer.launch({headless:true});
+  const page = await browser.newPage();
+  await page.goto(process.env.URIM);
+  await page.screenshot({path: process.env.THUMBNAIL_OUTPUTFILE});
+  await browser.close();
+})();
diff --git a/package-lock.json b/package-lock.json