Implement StringExclNull wrapper struct

This type can be used in query parameter structs to ensure that passed values do not contain null bytes.

Author: Turbo87

Cargo.lock

@@ -71,7 +71,7 @@ chrono = { version = "=0.4.39", default-features = false, features = ["serde"] }
 clap = { version = "=4.5.23", features = ["derive", "env", "unicode", "wrap_help"] }
 cookie = { version = "=0.18.1", features = ["secure"] }
 deadpool-diesel = { version = "=0.6.1", features = ["postgres", "tracing"] }
-derive_more = { version = "=1.0.0", features = ["deref", "deref_mut"] }
+derive_more = { version = "=1.0.0", features = ["deref", "deref_mut", "display"] }
 dialoguer = "=0.11.0"
 diesel = { version = "=2.2.6", features = ["postgres", "serde_json", "chrono", "numeric"] }
 diesel-async = { version = "=0.5.2", features = ["async-connection-wrapper", "deadpool", "postgres"] }

Cargo.toml

@@ -8,5 +8,6 @@ pub mod errors;
 mod io_util;
 mod request_helpers;
 pub mod rfc3339;
+pub mod string_excl_null;
 pub mod token;
 pub mod tracing;

src/util.rs

@@ -0,0 +1,24 @@
+use derive_more::{Deref, Display};
+use serde::Deserialize;
+
+/// A string that does not contain null bytes (`\0`).
+#[derive(Clone, Debug, Display, Deref, Deserialize, utoipa::ToSchema)]
+#[serde(try_from = "String")]
+pub struct StringExclNull(String);
+
+/// Error indicating that a string contained a null byte.
+#[derive(Debug, thiserror::Error)]
+#[error("string contains null byte")]
+pub struct StringExclNullError;
+
+impl TryFrom<String> for StringExclNull {
+    type Error = StringExclNullError;
+
+    fn try_from(s: String) -> Result<Self, Self::Error> {
+        if s.contains('\0') {
+            Err(StringExclNullError)
+        } else {
+            Ok(Self(s))
+        }
+    }
+}