event_id_from_base64(): Assume `event_id` is base64-encoded

A base64-encoded string I tested with didn't pass the regex test, and
was treated as an event ID even though it was an `eid`.

Instead of testing whether the input is a base64-encoded string with
regex, assume it's a base64-encoded string and try to decode it. If that
fails, assume it's a regular event ID.

3 files changed, 5 insertions, 43 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 978714c..d090f28 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,15 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
 [[package]]
-name = "aho-corasick"
-version = "0.7.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e37cfd5e7657ada45f742d6e99ca5788580b5c529dc78faf11ece6dc702656f"
-dependencies = [
- "memchr",
-]
-
-[[package]]
 name = "autocfg"
 version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -222,7 +213,6 @@ dependencies = [
  "home",
  "hyper",
  "hyper-rustls",
- "regex",
  "serde_json",
  "tokio",
  "yup-oauth2",
@@ -617,23 +607,6 @@ dependencies = [
 ]
 
 [[package]]
-name = "regex"
-version = "1.5.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
-]
-
-[[package]]
-name = "regex-syntax"
-version = "0.6.25"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
-
-[[package]]
 name = "ring"
 version = "0.16.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/Cargo.toml b/Cargo.toml
index ab4ed89..9c4fc75 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,6 @@ google-calendar3 = "2.0.4+20210327"
 home = "0.5.3"
 hyper = "0.14.7"
 hyper-rustls = "0.22.1"
-regex = "1.5.4"
 serde_json = "1.0.64"
 tokio = { version = "1.6.0", features = ["rt-multi-thread"] }
 yup-oauth2 = "5.1.0"
diff --git a/src/main.rs b/src/main.rs
index 9f4ad6a..a5e7a05 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,7 +4,6 @@ use google_calendar3::CalendarHub;
 use home;
 use hyper;
 use hyper_rustls;
-use regex::Regex;
 use tokio;
 use yup_oauth2 as oauth2;
 
@@ -153,20 +152,11 @@ fn secret_from_file() -> oauth2::ApplicationSecret {
 }
 
 fn event_id_from_base64(event_id: &str) -> String {
-    // Base64-matching regex from Xuanyuanzhiyuan
-    // (https://stackoverflow.com/users/1076906/xuanyuanzhiyuan) on Stack
-    // Overflow:
-    // https://stackoverflow.com/questions/8571501/how-to-check-whether-a-string-is-base64-encoded-or-not/8571649#8571649
-    let re = Regex::new(
-        "^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)?$",
-    ).unwrap();
-
-    if !re.is_match(event_id) {
-        return event_id.to_owned();
-    }
-
-    let decoded = &base64::decode(event_id).unwrap();
-    let id_email_pair = str::from_utf8(decoded).unwrap();
+    let decoded = match base64::decode(event_id) {
+        Ok(d) => d,
+        Err(_) => return event_id.to_owned(),
+    };
+    let id_email_pair = str::from_utf8(&decoded).unwrap();
     let values = id_email_pair.split(" ").collect::<Vec<_>>();
     let id = values.first().unwrap().to_string();