From 1e8aa95e7a93766e407cf2e08ae42504b16de27f Mon Sep 17 00:00:00 2001
From: Olivier 'reivilibre <olivier@librepush.net>
Date: Thu, 30 Mar 2023 23:09:39 +0100
Subject: [PATCH] Respect nofollow and noindex <meta> robots tags

Along with doing the right thing, this should speed up raking for us
---
 quickpeep_densedoc/src/lib.rs                 |  3 +-
 quickpeep_raker/src/raking.rs                 | 33 +++++++++++++++++--
 quickpeep_raker/src/raking/page_extraction.rs | 23 +++++++++++++
 3 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/quickpeep_densedoc/src/lib.rs b/quickpeep_densedoc/src/lib.rs
index e4af533..6741375 100644
--- a/quickpeep_densedoc/src/lib.rs
+++ b/quickpeep_densedoc/src/lib.rs
@@ -287,7 +287,8 @@ impl DenseTreeBuilder {
                         let nofollow = attrs
                             .get("rel")
                             .map(|rel: &str| {
-                                rel.split_whitespace()
+                                rel.split(|c: char| c.is_whitespace() || c == ',')
+                                    .filter(|s| !s.is_empty())
                                     .any(|rel_word: &str| rel_word.eq_ignore_ascii_case("nofollow"))
                             })
                             .unwrap_or(false);
diff --git a/quickpeep_raker/src/raking.rs b/quickpeep_raker/src/raking.rs
index 38c3937..78e3dae 100644
--- a/quickpeep_raker/src/raking.rs
+++ b/quickpeep_raker/src/raking.rs
@@ -1,4 +1,4 @@
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeSet, HashMap, HashSet};
 use std::error::Error;
 use std::fmt::{Debug, Display, Formatter};
 use std::io::Cursor;
@@ -15,7 +15,7 @@ use image::imageops::FilterType;
 use image::{GenericImageView, ImageFormat};
 use itertools::Itertools;
 use lazy_static::lazy_static;
-use log::{debug, info};
+use log::{debug, info, warn};
 use reqwest::header::HeaderMap;
 use reqwest::{Client, Response, Url};
 use serde::{Deserialize, Serialize};
@@ -112,6 +112,7 @@ pub enum TemporaryFailureReason {
 pub enum PermanentFailureReason {
     ResourceDenied(u16),
     DeniedToRobots,
+    IndexingDenied,
     WrongLanguage(String),
     UnknownContentType(String),
     ExceedsSizeLimit,
@@ -505,8 +506,34 @@ impl Raker {
                 document,
                 feeds,
                 antifeature_flags,
+                no_follow,
+                no_index,
             } => {
-                let references = references::find_references(&unreadable_document, &feeds, url);
+                if no_index {
+                    return Ok(RakeOutcome::PermanentFailure(PermanentFailure {
+                        reason: PermanentFailureReason::IndexingDenied,
+                    }));
+                }
+
+                let mut references = references::find_references(&unreadable_document, &feeds, url);
+
+                if no_follow {
+                    // Remove any link references
+                    for reference in references {
+                        match reference.kind {
+                            ReferenceKind::Link | ReferenceKind::HeaderLinkedFeed => (),
+                            ReferenceKind::CanonicalUrl
+                            | ReferenceKind::FeedEntry
+                            | ReferenceKind::SitemapEntry
+                            | ReferenceKind::SecureUpgrade
+                            | ReferenceKind::Redirect => {
+                                warn!("unexpected: refkind of {:?} being filtered due to meta nofollow. This is a bug.", reference.kind);
+                            }
+                        }
+                    }
+                    references = BTreeSet::new();
+                }
+
                 Ok(RakeOutcome::RakedPage(RakedPage {
                     page_entry: RakedPageEntry {
                         analysed_antifeatures: antifeature_flags,
diff --git a/quickpeep_raker/src/raking/page_extraction.rs b/quickpeep_raker/src/raking/page_extraction.rs
index 2ffb595..4ff6612 100644
--- a/quickpeep_raker/src/raking/page_extraction.rs
+++ b/quickpeep_raker/src/raking/page_extraction.rs
@@ -156,6 +156,25 @@ impl PageExtractionServiceInternal {
             }
         }
 
+        let mut no_follow = false;
+        let mut no_index = false;
+
+        // Find any restrictions on indexing this page or following any links.
+        if let Ok(robots_nodes) = root_node.select("meta[name=robots]") {
+            for node in robots_nodes {
+                if let Some(content) = node.attributes.borrow().get("content") {
+                    for directive in content
+                        .split(|c: char| c.is_whitespace() || c == ',')
+                        .filter(|s| !s.is_empty())
+                    {
+                        let none = directive.eq_ignore_ascii_case("none");
+                        no_follow |= directive.eq_ignore_ascii_case("nofollow") | none;
+                        no_index |= directive.eq_ignore_ascii_case("noindex") | none;
+                    }
+                }
+            }
+        }
+
         if language.is_none() {
             // Next fallback: prefer the content-language header baked into the page itself
             if let Ok(meta_node) = root_node.select_first("meta[http-equiv=content-language]") {
@@ -311,6 +330,8 @@ impl PageExtractionServiceInternal {
             document,
             feeds,
             antifeature_flags,
+            no_follow,
+            no_index,
         })
     }
 }
@@ -362,6 +383,8 @@ pub enum ExtractedPage {
         document: DenseDocument,
         feeds: Vec<Url>,
         antifeature_flags: AnalysisAntifeatures,
+        no_follow: bool,
+        no_index: bool,
     },
     Redirect {
         reason: RedirectReason,