[pve-devel] [PATCH proxmox 1/1] serde: add string_as_bool module for boolean string parsing

[Gabriel Goller]

Add new module to proxmox-serde that parses boolean values from various
string formats. Provides parse_bool function supporting common
representations (0/1, true/false, on/off, yes/no) along with
serializer/deserializer for these formats.

Note: this was copied over from proxmox-ve-config/firewall.

Signed-off-by: Gabriel Goller <g.goller at proxmox.com>
Co-authored-by: Stefan Hanreich <s.hanreich at proxmox.com>
---
 proxmox-serde/src/lib.rs | 84 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/proxmox-serde/src/lib.rs b/proxmox-serde/src/lib.rs
index c162834905c2..705ad430c953 100644
--- a/proxmox-serde/src/lib.rs
+++ b/proxmox-serde/src/lib.rs
@@ -260,3 +260,87 @@ pub mod string_as_base64url_nopad {
         String::from_utf8(bytes).map_err(|err| Error::custom(err.to_string()))
     }
 }
+
+/// Parse a bool from a string
+pub mod string_as_bool {
+    use std::fmt;
+
+    use serde::{
+        de::{Deserializer, Error, Visitor},
+        ser::Serializer,
+    };
+
+    /// Parse a boolean.
+    ///
+    /// values that parse as [`false`]: 0, false, off, no
+    /// values that parse as [`true`]: 1, true, on, yes
+    ///
+    /// # Examples
+    /// ```ignore
+    /// assert_eq!(parse_bool("false"), Ok(false));
+    /// assert_eq!(parse_bool("on"), Ok(true));
+    /// assert!(parse_bool("proxmox").is_err());
+    /// ```
+    pub fn parse_bool(value: &str) -> Result<bool, anyhow::Error> {
+        Ok(
+            if value == "0"
+                || value.eq_ignore_ascii_case("false")
+                || value.eq_ignore_ascii_case("off")
+                || value.eq_ignore_ascii_case("no")
+            {
+                false
+            } else if value == "1"
+                || value.eq_ignore_ascii_case("true")
+                || value.eq_ignore_ascii_case("on")
+                || value.eq_ignore_ascii_case("yes")
+            {
+                true
+            } else {
+                anyhow::bail!("not a boolean: {value:?}");
+            },
+        )
+    }
+
+    pub fn deserialize<'de, D: Deserializer<'de>>(
+        deserializer: D,
+    ) -> Result<Option<bool>, D::Error> {
+        struct V;
+
+        impl<'de> Visitor<'de> for V {
+            type Value = Option<bool>;
+
+            fn expecting(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                f.write_str("a boolean-like value")
+            }
+
+            fn visit_bool<E: Error>(self, v: bool) -> Result<Self::Value, E> {
+                Ok(Some(v))
+            }
+
+            fn visit_str<E: Error>(self, v: &str) -> Result<Self::Value, E> {
+                parse_bool(v).map_err(E::custom).map(Some)
+            }
+
+            fn visit_none<E: Error>(self) -> Result<Self::Value, E> {
+                Ok(None)
+            }
+
+            fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
+            where
+                D: Deserializer<'de>,
+            {
+                deserializer.deserialize_any(self)
+            }
+        }
+
+        deserializer.deserialize_any(V)
+    }
+
+    pub fn serialize<S: Serializer>(from: &Option<bool>, serializer: S) -> Result<S::Ok, S::Error> {
+        if *from == Some(true) {
+            serializer.serialize_str("1")
+        } else {
+            serializer.serialize_str("0")
+        }
+    }
+}
-- 
2.39.5