Add config-parsing-time check for argument count range

bunbun.default.yaml

@@ -34,13 +34,20 @@ groups:
     routes:
       # /ls is the only page that comes with bunbun besides the homepage. This
       # page provides a full list of routes and their groups they're in.
-      ls: &ls "/ls"
+      ls: &ls
+        path: "/ls"
+        # You can specify a maximum number of arguments, which are string
+        # delimited strings.
+        max_args: 0
+        # You can also specify a minimum amount of arguments.
+        # min_args: 1
       help:
-        # Bunbun supports all standard YAML features, so things like YAML pointers
-        # and references are supported.
-        path: *ls
+        path: &ls "/ls"
+        max_args: 0
         # Paths can be hidden from the listings page if desired.
         hidden: true
+      # Bunbun supports all standard YAML features, so things like YAML pointers
+      # and references are supported.
       list: *ls
   -
     # This is another group without a description

src/config.rs

@@ -2,7 +2,7 @@ use crate::BunBunError;
 use dirs::{config_dir, home_dir};
 use log::{debug, info, trace};
 use serde::{
-  de::{self, Deserializer, MapAccess, Visitor},
+  de::{self, Deserializer, MapAccess, Unexpected, Visitor},
   Deserialize, Serialize,
 };
 use std::collections::HashMap;
@@ -38,6 +38,8 @@ pub struct Route {
   pub path: String,
   pub hidden: bool,
   pub description: Option<String>,
+  pub min_args: Option<usize>,
+  pub max_args: Option<usize>,
 }
 
 impl FromStr for Route {
@@ -48,6 +50,8 @@ impl FromStr for Route {
       path: s.to_string(),
       hidden: false,
       description: None,
+      min_args: None,
+      max_args: None,
     })
   }
 }
@@ -63,11 +67,13 @@ impl<'de> Deserialize<'de> for Route {
     D: Deserializer<'de>,
   {
     #[derive(Deserialize)]
-    #[serde(field_identifier, rename_all = "lowercase")]
+    #[serde(field_identifier, rename_all = "snake_case")]
     enum Field {
       Path,
       Hidden,
       Description,
+      MinArgs,
+      MaxArgs,
     }
 
     struct RouteVisitor;
@@ -83,7 +89,7 @@ impl<'de> Deserialize<'de> for Route {
       where
         E: serde::de::Error,
       {
-        // This is infalliable
+        // This is infallable
         Ok(Self::Value::from_str(path).unwrap())
       }
 
@@ -94,6 +100,8 @@ impl<'de> Deserialize<'de> for Route {
         let mut path = None;
         let mut hidden = None;
         let mut description = None;
+        let mut min_args = None;
+        let mut max_args = None;
 
         while let Some(key) = map.next_key()? {
           match key {
@@ -115,6 +123,32 @@ impl<'de> Deserialize<'de> for Route {
               }
               description = Some(map.next_value()?);
             }
+            Field::MinArgs => {
+              if min_args.is_some() {
+                return Err(de::Error::duplicate_field("min_args"));
+              }
+              min_args = Some(map.next_value()?);
+            }
+            Field::MaxArgs => {
+              if max_args.is_some() {
+                return Err(de::Error::duplicate_field("max_args"));
+              }
+              max_args = Some(map.next_value()?);
+            }
+          }
+        }
+
+        if let (Some(min_args), Some(max_args)) = (min_args, max_args) {
+          if min_args > max_args {
+            {
+              return Err(de::Error::invalid_value(
+                Unexpected::Other(&format!(
+                  "argument count range {} to {}",
+                  min_args, max_args
+                )),
+                &"a valid argument count range",
+              ));
+            }
           }
         }
 
@@ -124,6 +158,8 @@ impl<'de> Deserialize<'de> for Route {
           path,
           hidden: hidden.unwrap_or_default(),
           description,
+          min_args,
+          max_args,
         })
       }
     }
@@ -337,7 +373,7 @@ mod route {
   fn serialize() {
     assert_eq!(
       &to_string(&Route::from_str("hello world").unwrap()).unwrap(),
-      "---\nroute_type: External\npath: hello world\nhidden: false\ndescription: ~"
+      "---\nroute_type: External\npath: hello world\nhidden: false\ndescription: ~\nmin_args: ~\nmax_args: ~"
     );
   }
 }

src/main.rs

@@ -66,6 +66,7 @@ async fn run() -> Result<(), BunBunError> {
     groups: conf.groups,
   }));
 
+  // Cannot be named _ or Rust will immediately drop it.
   let _watch = start_watch(Arc::clone(&state), conf_data, opts.large_config)?;
 
   HttpServer::new(move || {

src/routes.rs

@@ -90,7 +90,7 @@ pub async fn hop(
   let data = data.read().unwrap();
 
   match resolve_hop(&query.to, &data.routes, &data.default_route) {
-    (Some(path), args) => {
+    RouteResolution::Resolved { route: path, args } => {
       let resolved_template = match path {
         ConfigRoute {
           route_type: RouteType::Internal,
@@ -126,10 +126,16 @@ pub async fn hop(
         }
       }
     }
-    (None, _) => HttpResponse::NotFound().body("not found"),
+    RouteResolution::Unresolved => HttpResponse::NotFound().body("not found"),
   }
 }
 
+#[derive(Debug, PartialEq)]
+enum RouteResolution<'a> {
+  Resolved { route: &'a Route, args: String },
+  Unresolved,
+}
+
 /// Attempts to resolve the provided string into its route and its arguments.
 /// If a default route was provided, then this will consider that route before
 /// failing to resolve a route.
@@ -140,48 +146,61 @@ fn resolve_hop<'a>(
   query: &str,
   routes: &'a HashMap<String, Route>,
   default_route: &Option<String>,
-) -> (Option<&'a Route>, String) {
+) -> RouteResolution<'a> {
   let mut split_args = query.split_ascii_whitespace().peekable();
-  let command = match split_args.peek() {
-    Some(command) => command,
-    None => {
-      debug!("Found empty query, returning no route.");
-      return (None, String::new());
+  let maybe_route = {
+    match split_args.peek() {
+      Some(command) => routes.get(*command),
+      None => {
+        debug!("Found empty query, returning no route.");
+        return RouteResolution::Unresolved;
+      }
     }
   };
 
-  match (routes.get(*command), default_route) {
-    // Found a route
-    (Some(resolved), _) => (
-      Some(resolved),
-      match split_args.next() {
-        // Discard the first result, we found the route using the first arg
-        Some(_) => {
-          let args = split_args.collect::<Vec<&str>>().join(" ");
-          debug!("Resolved {} with args {}", resolved, args);
-          args
-        }
-        None => {
-          debug!("Resolved {} with no args", resolved);
-          String::new()
-        }
-      },
-    ),
-    // Unable to find route, but had a default route
-    (None, Some(route)) => {
-      let args = split_args.collect::<Vec<&str>>().join(" ");
-      debug!("Using default route {} with args {}", route, args);
-      match routes.get(route) {
-        Some(v) => (Some(v), args),
-        None => (None, String::new()),
-      }
-    }
-    // No default route and no match
-    (None, None) => {
-      debug!("Failed to resolve route!");
-      (None, String::new())
+  let args = split_args.collect::<Vec<_>>();
+  let arg_count = args.len();
+
+  // Try resolving with a matched command
+  if let Some(route) = maybe_route {
+    let args = if args.is_empty() { &[] } else { &args[1..] }.join(" ");
+    let arg_count = arg_count - 1;
+    if check_route(route, arg_count) {
+      debug!("Resolved {} with args {}", route, args);
+      return RouteResolution::Resolved { route, args };
     }
   }
+
+  // Try resolving with the default route, if it exists
+  if let Some(route) = default_route {
+    if let Some(route) = routes.get(route) {
+      if check_route(route, arg_count) {
+        let args = args.join(" ");
+        debug!("Using default route {} with args {}", route, args);
+        return RouteResolution::Resolved { route, args };
+      }
+    }
+  }
+
+  RouteResolution::Unresolved
+}
+
+/// Checks if the user provided string has the correct properties required by
+/// the route to be successfully matched.
+fn check_route(route: &Route, arg_count: usize) -> bool {
+  if let Some(min_args) = route.min_args {
+    if arg_count < min_args {
+      return false;
+    }
+  }
+
+  if let Some(max_args) = route.max_args {
+    if arg_count > max_args {
+      return false;
+    }
+  }
+
+  true
 }
 
 /// Runs the executable with the user's input as a single argument. Returns Ok
@@ -211,15 +230,18 @@ mod resolve_hop {
   fn generate_route_result<'a>(
     keyword: &'a Route,
     args: &str,
-  ) -> (Option<&'a Route>, String) {
-    (Some(keyword), String::from(args))
+  ) -> RouteResolution<'a> {
+    RouteResolution::Resolved {
+      route: keyword,
+      args: String::from(args),
+    }
   }
 
   #[test]
   fn empty_routes_no_default_yields_failed_hop() {
     assert_eq!(
       resolve_hop("hello world", &HashMap::new(), &None),
-      (None, String::new())
+      RouteResolution::Unresolved
     );
   }
 
@@ -231,7 +253,7 @@ mod resolve_hop {
         &HashMap::new(),
         &Some(String::from("google"))
       ),
-      (None, String::new())
+      RouteResolution::Unresolved
     );
   }
 
@@ -284,6 +306,57 @@ mod resolve_hop {
   }
 }
 
+#[cfg(test)]
+mod check_route {
+  use super::*;
+
+  fn create_route(
+    min_args: impl Into<Option<usize>>,
+    max_args: impl Into<Option<usize>>,
+  ) -> Route {
+    Route {
+      description: None,
+      hidden: false,
+      max_args: max_args.into(),
+      min_args: min_args.into(),
+      path: String::new(),
+      route_type: RouteType::External,
+    }
+  }
+
+  #[test]
+  fn no_min_arg_no_max_arg_counts() {
+    assert!(check_route(&create_route(None, None), 0));
+    assert!(check_route(&create_route(None, None), usize::MAX));
+  }
+
+  #[test]
+  fn min_arg_no_max_arg_counts() {
+    assert!(!check_route(&create_route(3, None), 0));
+    assert!(!check_route(&create_route(3, None), 2));
+    assert!(check_route(&create_route(3, None), 3));
+    assert!(check_route(&create_route(3, None), 4));
+    assert!(check_route(&create_route(3, None), usize::MAX));
+  }
+
+  #[test]
+  fn no_min_arg_max_arg_counts() {
+    assert!(check_route(&create_route(None, 3), 0));
+    assert!(check_route(&create_route(None, 3), 2));
+    assert!(check_route(&create_route(None, 3), 3));
+    assert!(!check_route(&create_route(None, 3), 4));
+    assert!(!check_route(&create_route(None, 3), usize::MAX));
+  }
+
+  #[test]
+  fn min_arg_max_arg_counts() {
+    assert!(!check_route(&create_route(2, 3), 1));
+    assert!(check_route(&create_route(2, 3), 2));
+    assert!(check_route(&create_route(2, 3), 3));
+    assert!(!check_route(&create_route(2, 3), 4));
+  }
+}
+
 #[cfg(test)]
 mod resolve_path {
   use super::resolve_path;

src/templates/opensearch.hbs

@@ -4,6 +4,6 @@
   <Description>Hop to where you need to go</Description>
   <InputEncoding>UTF-8</InputEncoding>
   <!--<Image width="16" height="16">data:image/x-icon;base64,</Image>-->
-  <Url type="text/html" template="http://{{hostname}}/hop?to={searchTerms}"></Url>
-  <Url type="application/x-moz-keywordsearch" template="http://{{hostname}}/hop?to={searchTerms}"></Url>
+  <Url type="text/html" template="http://{{hostname}}/hop?to={searchTerms}" />
+  <Url type="application/x-moz-keywordsearch" template="http://{{hostname}}/hop?to={searchTerms}" />
 </OpenSearchDescription>