Replace unmaintained crate difference by similar

Closes #54

Cargo.toml

@@ -30,7 +30,7 @@ async-object-pool = "0.1"
 crossbeam-utils = "0.8"
 futures-util = "0.3"
 basic-cookies = "0.1"
-difference = "2.0"
+similar = "2.1.0"
 levenshtein = "1.0"
 form_urlencoded = "1.0"
 

src/api/mock.rs

@@ -587,7 +587,7 @@ mod test {
                         Diff::Add(String::from("oa")),
                         Diff::Same(String::from("st")),
                     ],
-                    distance: 5,
+                    distance: 5.0,
                     tokenizer: Tokenizer::Line,
                 }),
             }],

src/common/data.rs

@@ -384,7 +384,7 @@ pub enum Diff {
 #[derive(Debug, Serialize, Deserialize)]
 pub struct DiffResult {
     pub differences: Vec<Diff>,
-    pub distance: i32,
+    pub distance: f32,
     pub tokenizer: Tokenizer,
 }
 

src/server/matchers/mod.rs

@@ -2,8 +2,8 @@ use std::collections::BTreeMap;
 use std::fmt::Display;
 
 use basic_cookies::Cookie;
-use difference::{Changeset, Difference};
 use serde::{Deserialize, Serialize};
+use similar::{ChangeTag, TextDiff};
 
 use crate::common::data::{
     Diff, DiffResult, HttpMockRequest, Mismatch, RequestRequirements, Tokenizer,
@@ -16,23 +16,21 @@ pub(crate) mod targets;
 pub(crate) mod transformers;
 
 pub(crate) fn diff_str(base: &str, edit: &str, tokenizer: Tokenizer) -> DiffResult {
-    let splitter = match tokenizer {
-        Tokenizer::Line => "\n",
-        Tokenizer::Word => " ",
-        Tokenizer::Character => "",
+    let changes = match tokenizer {
+        Tokenizer::Line => TextDiff::from_lines(base, edit),
+        Tokenizer::Word => TextDiff::from_words(base, edit),
+        Tokenizer::Character => TextDiff::from_chars(base, edit),
     };
 
-    let changes = Changeset::new(base, edit, splitter);
     DiffResult {
         tokenizer,
-        distance: changes.distance,
+        distance: changes.ratio(),
         differences: changes
-            .diffs
-            .iter()
-            .map(|d| match d {
-                Difference::Same(v) => Diff::Same(v.to_owned()),
-                Difference::Add(v) => Diff::Add(v.to_owned()),
-                Difference::Rem(v) => Diff::Rem(v.to_owned()),
+            .iter_all_changes()
+            .map(|change| match change.tag() {
+                ChangeTag::Equal => Diff::Same(change.to_string_lossy().to_string()),
+                ChangeTag::Insert => Diff::Add(change.to_string_lossy().to_string()),
+                ChangeTag::Delete => Diff::Rem(change.to_string_lossy().to_string()),
             })
             .collect(),
     }