From 7dc2369dd2d464ae1cf5bf46e7a961f9fd4c3990 Mon Sep 17 00:00:00 2001
From: Olivier <olivier@librepush.net>
Date: Mon, 28 Mar 2022 19:45:39 +0100
Subject: [PATCH] Some groundwork for pulling out JSON-LD dates

---
 Cargo.lock                                    |  1 +
 quickpeep_raker/Cargo.toml                    |  1 +
 quickpeep_raker/src/raking/page_extraction.rs | 72 ++++++++++++++++++-
 3 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/Cargo.lock b/Cargo.lock
index 37cec7d..15b75c5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3794,6 +3794,7 @@ dependencies = [
  "reqwest",
  "serde",
  "serde_bare",
+ "serde_json",
  "signal-hook 0.3.13",
  "sitemap",
  "smartstring",
diff --git a/quickpeep_raker/Cargo.toml b/quickpeep_raker/Cargo.toml
index 89750ff..fe5c9d4 100644
--- a/quickpeep_raker/Cargo.toml
+++ b/quickpeep_raker/Cargo.toml
@@ -22,6 +22,7 @@ kuchiki = "0.8.1"
 html5ever = "0.25.1"
 serde = { version = "1.0.136", features = ["derive"] }
 serde_bare = "0.5.0"
+serde_json = "1.0.79"
 
 toml = "0.5.8"
 
diff --git a/quickpeep_raker/src/raking/page_extraction.rs b/quickpeep_raker/src/raking/page_extraction.rs
index 1992b39..5e2b6ff 100644
--- a/quickpeep_raker/src/raking/page_extraction.rs
+++ b/quickpeep_raker/src/raking/page_extraction.rs
@@ -4,15 +4,17 @@ use crate::raking::analysis::{
 use crate::raking::{normalise_language, RedirectReason, FEED_LINK_MIME_TYPES};
 use adblock::engine::Engine;
 use anyhow::{bail, Context};
+use chrono::{DateTime, Utc};
 use html5ever::tendril::TendrilSink;
 use itertools::Itertools;
 use kuchiki::NodeRef;
-use log::{debug, error, warn};
+use log::{debug, error, trace, warn};
 use quickpeep_densedoc::{DenseDocument, DenseHead, DenseTree};
 use quickpeep_structs::rake_entries::AnalysisAntifeatures;
 use quickpeep_utils::lazy::Lazy;
 use reqwest::header::HeaderMap;
 use reqwest::Url;
+use serde::{Deserialize, Serialize};
 use tokio::runtime;
 use tokio::sync::mpsc::Sender;
 use tokio::sync::{mpsc, oneshot};
@@ -234,6 +236,8 @@ impl PageExtractionServiceInternal {
             }
         }
 
+        find_page_metadata(root_node.clone())?;
+
         let mut readability =
             quickpeep_moz_readability::Readability::new_from_node(root_node.clone());
         if let Err(err) = readability.parse(url.as_str()) {
@@ -274,6 +278,47 @@ impl PageExtractionServiceInternal {
     }
 }
 
+fn parse_json_ld_date(input: String) -> Option<DateTime<Utc>> {
+    DateTime::parse_from_rfc3339(&input)
+        .ok()
+        .map(|dt| dt.with_timezone(&Utc))
+}
+
+pub fn find_page_metadata(root_node: NodeRef) -> anyhow::Result<PageMetadata> {
+    let mut meta = PageMetadata {
+        publication_date: None,
+        creation_date: None,
+    };
+
+    match root_node.select("script[type='application/ld+json']") {
+        Ok(ld_nodes) => {
+            for ld_node in ld_nodes {
+                if let Some(_element) = ld_node.as_node().as_element() {
+                    let json_text = ld_node.text_contents();
+                    match serde_json::de::from_str::<JsonLdMetadata>(json_text.as_str()) {
+                        Ok(jld) => {
+                            let date_published =
+                                jld.date_published.map(parse_json_ld_date).flatten();
+                            let date_created = jld.date_created.map(parse_json_ld_date).flatten();
+                            if date_published.is_some() {
+                                meta.publication_date = date_published;
+                            }
+                            if date_created.is_some() {
+                                meta.creation_date = date_created;
+                            }
+                        }
+                        Err(err) => {
+                            trace!("Bad JSON-LD: {:?}", err);
+                        }
+                    }
+                }
+            }
+            Ok(meta)
+        }
+        Err(()) => Ok(meta),
+    }
+}
+
 pub enum ExtractedPage {
     Success {
         document: DenseDocument,
@@ -285,3 +330,28 @@ pub enum ExtractedPage {
         new_url: Url,
     },
 }
+
+/// Metadata that may be found in a JSON-LD snippet on the page.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct JsonLdMetadata {
+    #[serde(rename = "@context")]
+    #[serde(default)]
+    pub context: Option<String>,
+
+    #[serde(rename = "@type")]
+    #[serde(default)]
+    pub entity_type: Option<String>,
+
+    #[serde(rename = "datePublished")]
+    #[serde(default)]
+    pub date_published: Option<String>,
+
+    #[serde(rename = "dateCreated")]
+    #[serde(default)]
+    pub date_created: Option<String>,
+}
+
+pub struct PageMetadata {
+    publication_date: Option<DateTime<Utc>>,
+    creation_date: Option<DateTime<Utc>>,
+}