don't panic if we can't parse the query string

the query string comes from external input, so it should be more robust

1 files changed, 19 insertions, 16 deletions

diff --git a/src/http.rs b/src/http.rs
index 2763636..9096298 100644
--- a/src/http.rs
+++ b/src/http.rs
@@ -1,27 +1,28 @@
 use std::collections::HashMap;
 
-pub fn parse_query_string (string: &str) -> HashMap<&str, &str> {
+pub fn parse_query_string (string: &str) -> Option<HashMap<&str, &str>> {
     let mut map = HashMap::new();
     let mut offset = 0;
     let len = string.as_bytes().len();
     while offset < len {
         let key_start = offset;
-        let key_end = key_start + string[key_start..]
-            .find('=')
-            .unwrap_or_else(|| {
-                panic!("couldn't parse query string '{:?}'", string)
-            });
-        let key = &string[key_start..key_end];
-        let value_start = key_end + 1;
-        let value_end = value_start + string[value_start..]
-            .find('&')
-            .unwrap_or_else(|| string[value_start..].as_bytes().len());
-        let value = &string[value_start..value_end];
-        map.insert(key, value);
-        offset = value_end + 1;
+        if let Some(found) = string[key_start..].find('=') {
+            let key_end = key_start + found;
+            let key = &string[key_start..key_end];
+            let value_start = key_end + 1;
+            let value_end = value_start + string[value_start..]
+                .find('&')
+                .unwrap_or_else(|| string[value_start..].as_bytes().len());
+            let value = &string[value_start..value_end];
+            map.insert(key, value);
+            offset = value_end + 1;
+        }
+        else {
+            return None;
+        }
     }
 
-    return map;
+    return Some(map);
 }
 
 pub fn create_query_string (params: HashMap<&str, &str>) -> String {
@@ -46,7 +47,9 @@ fn test_parse_query_string () {
     expected.insert("foo", "bar");
     expected.insert("baz", "qux");
     expected.insert("zap", "zazzle");
-    assert_eq!(got, expected);
+    assert_eq!(got, Some(expected));
+
+    assert_eq!(parse_query_string("foo=bar&baz=qux&zapzazzle"), None);
 }
 
 #[test]