Have Media db return optional content_type, conversion fixes

src/utils.rs

@@ -1,6 +1,7 @@
 use argon2::{Config, Variant};
 use cmp::Ordering;
 use rand::prelude::*;
+use ruma::serde::{try_from_json_map, CanonicalJsonError, CanonicalJsonObject};
 use sled::IVec;
 use std::{
     cmp,
@@ -94,3 +95,19 @@ pub fn common_elements(
             .all(|b| b)
     }))
 }
+
+/// Fallible conversion from any value that implements `Serialize` to a `CanonicalJsonObject`.
+///
+/// `value` must serialize to an `serde_json::Value::Object`.
+pub fn to_canonical_object<T: serde::Serialize>(
+    value: T,
+) -> Result<CanonicalJsonObject, CanonicalJsonError> {
+    use serde::ser::Error;
+
+    match serde_json::to_value(value).map_err(CanonicalJsonError::SerDe)? {
+        serde_json::Value::Object(map) => try_from_json_map(map),
+        _ => Err(CanonicalJsonError::SerDe(serde_json::Error::custom(
+            "Value must be an object",
+        ))),
+    }
+}