1 files changed, 19 insertions, 0 deletions
diff --git a/src/metadata.rs b/src/metadata.rs
index 893f6e2..caaebc8 100644
--- a/src/metadata.rs
+++ b/src/metadata.rs
@@ -7,6 +7,8 @@ use std::{mem, slice, str};
 
 use crate::error::{Error, Result};
 
+const BINARY_ERROR_DETAILS_KEY: &str = "grpc-status-details-bin";
+
 fn normalize_key(key: &str, binary: bool) -> Result<Cow<'_, str>> {
     if key.is_empty() {
         return Err(Error::InvalidMetadata(
@@ -107,6 +109,13 @@ impl MetadataBuilder {
         Ok(self.add_metadata(&key, value))
     }
 
+    /// Set binary error details to support rich error model.
+    ///
+    /// See also https://grpc.io/docs/guides/error/#richer-error-model.
+    pub(crate) fn set_binary_error_details(&mut self, value: &[u8]) -> &mut MetadataBuilder {
+        self.add_metadata(BINARY_ERROR_DETAILS_KEY, value)
+    }
+
     /// Create `Metadata` with configured entries.
     pub fn build(mut self) -> Metadata {
         unsafe {
@@ -214,6 +223,16 @@ impl Metadata {
             metadata: p,
         })
     }
+
+    /// Search for binary error details.
+    pub(crate) fn search_binary_error_details(&self) -> &[u8] {
+        for (k, v) in self.iter() {
+            if k == BINARY_ERROR_DETAILS_KEY {
+                return v;
+            }
+        }
+        &[]
+    }
 }
 
 impl Clone for Metadata {