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use kitchen_sink::Origin;
use std::cmp::Ordering;
use std::{fs, path::Path};
use tantivy::{self, collector::TopDocs, query::QueryParser, schema::*, Index, IndexWriter};
const CRATE_SCORE_MAX: f64 = 1000000.0;
pub struct CrateSearchIndex {
/// Origin.to_str
origin_pkey: Field,
/// as-is
crate_name_field: Field,
/// ", "-separated
keywords_field: Field,
description_field: Field,
readme_field: Field,
/// raw number
monthly_downloads: Field,
/// semver string
crate_version: Field,
/// number in range 0..=SCORE_MAX denoting desirability of the crate
crate_score: Field,
tantivy_index: Index,
}
#[derive(Debug, Clone)]
pub struct CrateFound {
pub origin: Origin,
pub crate_name: String,
pub description: String,
pub keywords: String,
pub score: f32,
pub version: String,
pub monthly_downloads: u64,
}
pub struct Indexer {
index: CrateSearchIndex,
writer: IndexWriter,
}
impl CrateSearchIndex {
pub fn new(index_dir: impl AsRef<Path>) -> tantivy::Result<Self> {
let index_dir = index_dir.as_ref().join("tantivy2");
if !index_dir.exists() {
return Self::reset_db_to_empty(&index_dir);
}
let tantivy_index = Index::open_in_dir(index_dir)?;
let schema = tantivy_index.schema();
Ok(Self {
tantivy_index,
origin_pkey: schema.get_field("origin").expect("schema"),
crate_name_field: schema.get_field("crate_name").expect("schema"),
keywords_field: schema.get_field("keywords").expect("schema"),
description_field: schema.get_field("description").expect("schema"),
readme_field: schema.get_field("readme").expect("schema"),
monthly_downloads: schema.get_field("monthly_downloads").expect("schema"),
crate_version: schema.get_field("crate_version").expect("schema"),
crate_score: schema.get_field("crate_score").expect("schema"),
})
}
fn reset_db_to_empty(index_dir: &Path) -> tantivy::Result<Self> {
let _ = fs::create_dir_all(index_dir);
let mut schema_builder = SchemaBuilder::default();
let origin_pkey = schema_builder.add_text_field("origin", STRING | STORED);
let crate_name_field = schema_builder.add_text_field("crate_name", TEXT | STORED);
let keywords_field = schema_builder.add_text_field("keywords", TEXT | STORED);
let description_field = schema_builder.add_text_field("description", TEXT | STORED);
let text_field_indexing = TextFieldIndexing::default().set_tokenizer("en_stem").set_index_option(IndexRecordOption::WithFreqs);
let text_options = TextOptions::default().set_indexing_options(text_field_indexing);
let readme_field = schema_builder.add_text_field("readme", text_options);
let crate_version = schema_builder.add_text_field("crate_version", STRING | STORED);
let monthly_downloads = schema_builder.add_u64_field("monthly_downloads", STORED);
let crate_score = schema_builder.add_u64_field("crate_score", STORED);
let schema = schema_builder.build();
let tantivy_index = Index::create_in_dir(index_dir, schema)?;
Ok(Self { tantivy_index, origin_pkey, crate_name_field, keywords_field, description_field, readme_field, monthly_downloads, crate_version, crate_score })
}
/// if sort_by_query_relevance is false, sorts by internal crate score (relevance is still used to select the crates)
pub fn search(&self, query_text: &str, limit: usize, sort_by_query_relevance: bool) -> tantivy::Result<Vec<CrateFound>> {
let query_text = query_text.trim();
let mut query_parser = QueryParser::for_index(&self.tantivy_index, vec![
self.crate_name_field, self.keywords_field, self.description_field, self.readme_field,
]);
query_parser.set_conjunction_by_default();
let query = query_parser.parse_query(query_text)
.or_else(|_| {
let mangled_query: String = query_text.chars().map(|ch| {
if ch.is_alphanumeric() {ch.to_ascii_lowercase()} else {' '}
}).collect();
query_parser.parse_query(mangled_query.trim())
})?;
let reader = self.tantivy_index.reader()?;
let searcher = reader.searcher();
let top_docs = searcher.search(&*query, &TopDocs::with_limit(limit+10+limit/3))?;
let mut docs = top_docs.into_iter().enumerate().map(|(i, (relevance_score, doc_address))| {
let retrieved_doc = searcher.doc(doc_address)?;
let mut doc = self.tantivy_index.schema().to_named_doc(&retrieved_doc).0;
let mut crate_base_score = take_int(doc.get("crate_score")) as f64;
let crate_name = take_string(doc.remove("crate_name"));
Ok(CrateFound {
origin: Origin::from_str(take_string(doc.remove("origin"))),
score: if sort_by_query_relevance {
// first few crates can be ordered by tantivy's relevance
let position_bonus = if i < 4 {CRATE_SCORE_MAX / (i as f64 + 8.)} else {0.};
// bonus for exact match
if crate_name == query_text {
crate_base_score += CRATE_SCORE_MAX / 8.;
}
(relevance_score as f64 * (crate_base_score + position_bonus)) as f32
} else {
crate_base_score as f32
},
crate_name,
description: take_string(doc.remove("description")),
keywords: take_string(doc.remove("keywords")),
version: take_string(doc.remove("crate_version")),
monthly_downloads: take_int(doc.get("monthly_downloads")),
})
})
.collect::<tantivy::Result<Vec<_>>>()?;
// workaround for bug or corrupted index that caused dupes
docs.dedup_by(|a, b| a.crate_name == b.crate_name);
// re-sort using our base score
docs.sort_by(|a,b| b.score.partial_cmp(&a.score).unwrap_or(Ordering::Equal));
docs.truncate(limit); // search picked a few more results to cut out chaff using crate_score
Ok(docs)
}
}
fn take_string(val: Option<Vec<Value>>) -> String {
match val {
Some(mut val) => match val.remove(0) {
Value::Str(s) => s,
_ => panic!("invalid value type"),
},
_ => String::new(),
}
}
fn take_int(val: Option<&Vec<Value>>) -> u64 {
match val {
Some(val) => match val.get(0) {
Some(Value::U64(s)) => *s,
Some(Value::I64(s)) => *s as u64,
_ => panic!("invalid value type"),
},
_ => 0,
}
}
impl Indexer {
pub fn new(index: CrateSearchIndex) -> tantivy::Result<Self> {
Ok(Self { writer: index.tantivy_index.writer(250_000_000)?, index })
}
/// score is float 0..=1 range
pub fn add(&mut self, origin: &Origin, crate_name: &str, version: &str, description: &str, keywords: &[&str], readme: Option<&str>, monthly_downloads: u64, score: f64) {
let origin = origin.to_str();
// delete old doc if any
let pkey = Term::from_field_text(self.index.origin_pkey, &origin);
self.writer.delete_term(pkey);
// index new one
let mut doc = Document::default();
doc.add_text(self.index.origin_pkey, &origin);
doc.add_text(self.index.crate_name_field, crate_name);
doc.add_text(self.index.keywords_field, &keywords.join(", "));
doc.add_text(self.index.description_field, description);
if let Some(readme) = readme {
doc.add_text(self.index.readme_field, readme);
}
doc.add_text(self.index.crate_version, version);
doc.add_u64(self.index.monthly_downloads, monthly_downloads);
doc.add_u64(self.index.crate_score, (score * CRATE_SCORE_MAX).ceil() as u64);
self.writer.add_document(doc);
}
pub fn commit(&mut self) -> tantivy::Result<()> {
self.writer.commit()?;
Ok(())
}
pub fn bye(self) -> tantivy::Result<CrateSearchIndex> {
self.writer.wait_merging_threads()?;
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