add options for empty frontmatter

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mdlint"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2021"
 
 [profile.release]

src/args.rs

@@ -5,6 +5,8 @@ pub fn get_args() -> ArgMatches {
         .about("Lint markdown frontmatter using JSON Schema")
         .arg(arg!([schema] "Schema file used for validation").required(true))
         .arg(arg!([file] "File to validate").required(true))
-        .arg(arg!(--greedy "Require all properties to be present even if they are not strictly required in schema").required(false))
+        .arg(arg!(-g --greedy "Require all properties to be present even if they are not strictly required in schema").required(false))
+        .arg(clap::Arg::new("empty-frontmatter").short('e').long("empty-frontmatter").conflicts_with("ignore-missing-frontmatter").required(false).num_args(0).help("Treat missing frontmatter as empty frontmatter"))
+        .arg(clap::Arg::new("ignore-missing-frontmatter").short('i').long("ignore-missing-frontmatter").conflicts_with("empty-frontmatter").required(false).num_args(0).help("Dont print an error when no frontmatter has been found"))
         .get_matches()
 }

src/main.rs

@@ -9,13 +9,17 @@ trait ErrorExit {
     fn quit_on_error(self, msg: &str) -> Self::T;
 }
 
-impl<T, E> ErrorExit for Result<T, E> {
+impl<T, E: std::fmt::Debug> ErrorExit for Result<T, E> {
     type T = T;
 
     fn quit_on_error(self, msg: &str) -> T {
         self.map_or_else(
-            |_| {
-                eprintln!("{} {msg}", Style::new().red().apply_to("Error:"));
+            |e| {
+                if msg.is_empty() {
+                    eprintln!("{} {e:?}", Style::new().red().apply_to("Error:"));
+                } else {
+                    eprintln!("{} {msg}", Style::new().red().apply_to("Error:"));
+                }
                 std::process::exit(1);
             },
             |res| res,
@@ -66,6 +70,34 @@ fn require_everything(schema: &mut serde_json::Value) {
     }
 }
 
+fn get_frontmatter_from_file(file: &str, args: &clap::ArgMatches) -> serde_yaml::Value {
+    let frontmatter_str = get_frontmatter(&std::fs::read_to_string(file).quit_on_error(&format!(
+        "Could not read markdown file '{}'",
+        Style::new().blue().apply_to(file)
+    )));
+
+    let frontmatter_str = frontmatter_str.map_or_else(
+        || {
+            if args.get_flag("ignore-missing-frontmatter") {
+                std::process::exit(0);
+            }
+            if !args.get_flag("empty-frontmatter") {
+                Result::<(), ()>::Err(()).quit_on_error(&format!(
+                    "Could not parse frontmatter '{}'",
+                    Style::new().blue().apply_to(file)
+                ));
+            }
+            "{}".to_string()
+        },
+        |s| s,
+    );
+
+    serde_yaml::from_str(&frontmatter_str).quit_on_error(&format!(
+        "Frontmatter is no valid yaml '{}'",
+        Style::new().blue().apply_to(file)
+    ))
+}
+
 fn main() {
     let args = args::get_args();
 
@@ -86,21 +118,9 @@ fn main() {
         .compile(&schema)
         .quit_on_error("Schema is not valid");
 
-    let frontmatter = serde_yaml::from_str(
-        &get_frontmatter(&std::fs::read_to_string(file).quit_on_error(&format!(
-            "Could not read markdown file '{}'",
-            Style::new().blue().apply_to(file)
-        )))
-        .ok_or(0)
-        .quit_on_error(&format!(
-            "Could not parse frontmatter '{}'",
-            Style::new().blue().apply_to(file)
-        )),
-    )
-    .quit_on_error(&format!(
-        "Frontmatter is no valid yaml '{}'",
-        Style::new().blue().apply_to(file)
-    ));
+    let frontmatter = get_frontmatter_from_file(file, &args);
+    let frontmatter: serde_json::Value =
+        serde_json::from_str(&serde_json::to_string(&frontmatter).unwrap()).unwrap();
 
     let result = comp_schema.validate(&frontmatter);