Merge pull request #5 from elsevierlabs-os/dev

New features

Author: RinkeHoekstra

media/js/cpldviewer.js

@@ -6,7 +6,7 @@
   "license": "SEE LICENSE IN LICENSE.md",
   "repository": "https://github.com/elsevierlabs-os/cpld-viewer.git",
   "icon": "media/img/cpld-icon.png",
-  "version": "1.0.4",
+  "version": "1.0.5",
   "engines": {
     "vscode": "^1.61.0"
   },

package.json

@@ -0,0 +1,17 @@
+# Simple Linked Data Redirect Proxy
+
+The `proxy.py` script in this folder can be used as a simple proxy for redirecting requests from the viewer to Linked Data services on the web. This is particularly useful when:
+
+* The services require authentication
+* The services do not dereference from the original Linked Data URI
+* The services are not CORS enabled.
+
+## Configuration
+
+* Rename `config.template.yml` to `config.yml`
+* Make adjustments in the config file to suit your needs:
+  * The `rewrites` dictionary should contain entries that match the requested IRI to a regex, with an `id` part. 
+  * If a match is found, this `id` part is then concatenated at the back of the `rewrite_url_prefix` and the request is forwarded to that.
+  * The `apis` dictionary are also triggered by a regex match.
+  * Create an object for each api, including an address for retrieving a JSON web token.
+* The proxy will always forward only to the first service that matches.

proxy/README.md

@@ -0,0 +1,14 @@
+apis:
+  API_1_NAME:
+    regex: "https://data.elsevier.com/health/(core/)?(?P<id>.*)"
+    token_url: "URL FOR RETRIEVING WEBTOKEN"
+    key: "SECRET KEY TO OBTAIN TOKEN"
+    secret: "SECRET TO OBTAIN TOKEN"
+    api_url: "API URL. The <id> value is concatenated at the end of this URL."
+rewrites:
+  REWRITE_1_NAME:
+    regex: "https://some.example.iri/namespace/(?P<id>.*)"
+    rewrite_url_prefix: "https://some.different.example/iri/namespace/to/which/to/redirect/"
+  REWRITE_2_NAME:
+    regex: "https://some.other.example.iri/namespace/(?P<id>.*)"
+    rewrite_url_prefix: "https://some.other.different.example/iri/namespace/to/which/to/redirect/"

proxy/config.template.yml

@@ -0,0 +1,85 @@
+import requests
+import re
+import yaml
+import rfc3987
+from flask import Flask, request, make_response
+from flask_cors import CORS
+
+app = Flask(__name__)
+CORS(app)
+
+
+try:
+    config = yaml.safe_load(open("config.yml"));
+except:
+    config = {'apis': {}, 'rewrites': {}}
+
+@app.route("/browse", methods=["GET"])
+def browse():
+    iri = request.args.get('uri', None)
+
+
+    is_iri = rfc3987.match(iri)
+    if is_iri is None:
+        return make_response({"ERROR": f"{is_iri} is not a valid IRI according to RFC3987"},400)
+
+    response = None
+    if iri is not None:
+        print(iri)
+        passed_through_response = do_request(iri, request.headers)
+        response = make_response(passed_through_response.content)
+        response.headers['Content-Type'] = passed_through_response.headers['Content-Type']
+    else: 
+        response = make_response({})
+        response.headers['Content-Type'] = "application/ld+json"
+    
+    return response
+
+def do_request(iri, headers):
+    
+    print(headers.get("Accept"))
+    proxy_headers = {
+        "Accept": headers.get("Accept")
+    }
+
+    for api in config['apis'].values():
+        regex = api['regex']
+        token_url = api['token_url']
+        key = api['key']
+        secret = api['secret']
+        api_url = api['api_url']
+
+        # Test for match against H-Graph API
+        match = re.match(regex,iri)
+        
+        if match != None:
+            # Get token
+            response = requests.post(token_url, auth=(key,secret))
+            if response.status_code == 200:
+                access_token = response.json()['access_token']
+                print(access_token)
+            else:
+                raise Exception("API Token could not be retrieved for API call")
+            
+            api_call_url = api_url + match.group("id")
+
+            proxy_headers["Authorization"] = f"Bearer {access_token}"
+
+            print(api_call_url)
+            try:
+                return requests.get(api_call_url, headers=proxy_headers)
+            except Exception as e:
+                raise e
+
+    for rewrite in config['rewrites'].values():
+        regex = rewrite['regex']
+        rewrite_url_prefix = rewrite['rewrite_url_prefix']
+
+        match = re.match(regex, iri)
+        if match != None:
+            rewrite_call_url = rewrite_url_prefix + match.group('id')
+            print(rewrite_call_url)
+            return requests.get(rewrite_call_url, headers=proxy_headers)
+
+    
+    return requests.get(iri, headers=proxy_headers)

proxy/proxy.py

@@ -0,0 +1,20 @@
+[tool.poetry]
+name = "linked-data-proxy"
+version = "0.1.0"
+description = ""
+authors = ["Rinke Hoekstra <r.hoekstra@elsevier.com>"]
+readme = "README.md"
+packages = [{include = "linked_data_proxy"}]
+
+[tool.poetry.dependencies]
+python = "^3.10"
+requests = "^2.31.0"
+flask = "^2.3.2"
+flask-cors = "^3.0.10"
+pyyaml = "^6.0"
+rfc3987 = "^1.3.8"
+
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"

proxy/pyproject.toml

@@ -59,6 +59,12 @@ body {
   background: #E0E4CC;
 }
 
+.object.literal {
+  background: #e0e4cc7e !important;
+  font-style: oblique;
+  cursor:text;
+}
+
 .cpld-box {
   background: rgba(170, 170, 170, 0.4);
   cursor: pointer;
@@ -91,6 +97,23 @@ body {
     grid-template-columns: repeat(3, 1fr);
 }
 
+.error-container {
+  min-height: 300px;
+  min-width: 100%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.error {
+  border: 1px black;
+  background-color: #fa690029;
+  color: black;
+  border-radius: 5px;
+  padding: 3em;
+  text-align: center;
+}
+
 .toast {
   max-width: 420px;
 }