Adds Node wrappers for handling redirect resources

Updates README to demonstrate redirect handling, includes logging to stderr for some of the worse failure cases

README.md

@@ -41,10 +41,14 @@ Note the Node.js module has overheads inherent to boundary crossing between JS a
 
 ```js
 const AdBlockClient = require('adblock-rs');
-let rules = fs.readFileSync('./data/easylist.to/easylist/easylist.txt', { encoding: 'utf-8' }).split('\n');
+let el_rules = fs.readFileSync('./data/easylist.to/easylist/easylist.txt', { encoding: 'utf-8' }).split('\n');
+let ubo_unbreak_rules = fs.readFileSync('./data/uBlockOrigin/unbreak.txt', { encoding: 'utf-8' }).split('\n');
+let rules = el_rules.concat(ubo_unbreak_rules);
+let resources = fs.readFileSync('./data/uBlockOrigin/resources.txt', { encoding: 'utf-8' });
 
 // create client with debug = true
 const client = new AdBlockClient.Engine(rules, true);
+client.updateResources(resources);
 
 const serializedArrayBuffer = client.serialize(); // Serialize the engine to an ArrayBuffer
 
@@ -55,12 +59,13 @@ console.log("Matching:", client.check("http://example.com/-advertisement-icon.",
 console.log("Matching:", client.check("http://example.com/-advertisement-icon.", "http://example.com/helloworld", "image", true))
 // No, but still with debugging info
 console.log("Matching:", client.check("https://github.githubassets.com/assets/frameworks-64831a3d.js", "https://github.com/AndriusA", "script", true))
+// Example that inlcludes a redirect response
+console.log("Matching:", client.check("https://bbci.co.uk/test/analytics.js", "https://bbc.co.uk", "script", true))
 ```
 
 
 ## TODO
 
-- [ ] Generate redirect addresses based on provided resources.txt (uBo style)
 - [ ] Function for extracting CSP directives
 - [ ] Generate string representation of a rule when debug mode is off (i.e. initial rule is not available)
 - [ ] Cosmetic filters

native/src/lib.rs

@@ -109,6 +109,18 @@ declare_types! {
             };
             Ok(JsNull::new().upcast())
         }
+
+        method updateResources(mut cx) {
+            let resources: String = cx.argument::<JsString>(0)?.value();
+
+            let mut this = cx.this();
+            let guard = cx.lock();
+            {
+                let mut engine = this.borrow_mut(&guard);
+                engine.with_resources(&resources);
+            }
+            Ok(JsNull::new().upcast())
+        }
     }
 }
 

src/blocker.rs

@@ -117,6 +117,9 @@ impl Blocker {
                         Some(data_url.trim().to_owned())
                     } else {
                         // TOOD: handle error - throw?
+                        if self.debug {
+                            eprintln!("Matched rule with redirect option but did not find corresponding resource to send");
+                        }
                         None
                     }
                 } else {

src/engine.rs

@@ -51,7 +51,7 @@ impl Engine {
         let gz = GzDecoder::new(serialized);
         let blocker = bincode::deserialize_from(gz)
             .or_else(|e| {
-                println!("Error deserializing: {:?}", e);
+                eprintln!("Error deserializing: {:?}", e);
                 Err(BlockerError::DeserializationError)
             })?;
         self.blocker = blocker;
@@ -65,6 +65,7 @@ impl Engine {
             self.blocker.check(&request)
         })
         .unwrap_or_else(|_e| {
+            eprintln!("Error parsing request, returning no match");
             BlockerResult {
                 matched: false,
                 explicit_cancel: false,