refactor(media): share one external proxy url codec across every service (#1794)

Cargo.lock

@@ -1777,6 +1777,7 @@ dependencies = [
  "axum",
  "base64",
  "clap",
+ "fluxer_common",
  "hmac 0.13.0",
  "hyper 1.10.1",
  "hyper-util",
@@ -1800,6 +1801,7 @@ dependencies = [
  "anyhow",
  "base64",
  "fluxer-svc",
+ "fluxer_common",
  "hmac 0.13.0",
  "moka",
  "reqwest",
@@ -1836,6 +1838,7 @@ dependencies = [
  "cc",
  "clap",
  "criterion",
+ "fluxer_common",
  "hex",
  "hmac 0.13.0",
  "http 1.4.2",
@@ -1875,6 +1878,7 @@ dependencies = [
  "chrono",
  "criterion",
  "fluxer-svc",
+ "fluxer_common",
  "fluxer_markdown_parser",
  "futures",
  "hmac 0.13.0",
@@ -1943,6 +1947,7 @@ dependencies = [
  "encoding_rs",
  "entities",
  "fluxer-svc",
+ "fluxer_common",
  "hmac 0.13.0",
  "infer",
  "moka",
@@ -2038,10 +2043,14 @@ dependencies = [
  "aws-credential-types",
  "aws-sigv4",
  "axum",
+ "base64",
+ "hmac 0.13.0",
  "maxminddb",
  "moka",
  "reqwest",
  "serde_json",
+ "sha2 0.11.0",
+ "thiserror",
  "time",
  "tracing",
  "urlencoding",

fluxer_common/Cargo.toml

@@ -15,4 +15,8 @@ reqwest = { version = "0.13.4", default-features = false, features = ["blocking"
 serde_json = "1.0.150"
 time = { version = "0.3.47", features = ["formatting", "macros", "parsing"] }
 tracing = "0.1.44"
+base64 = "0.22"
+hmac = "0.13.0"
+sha2 = "0.11.0"
+thiserror = "2"
 urlencoding = "2.1.3"

fluxer_common/src/external_media_path.rs

@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+use base64::prelude::*;
+use thiserror::Error;
+
+const V2_PREFIX: &str = "v2/";
+
+#[derive(Debug, Error, Eq, PartialEq)]
+pub enum ExternalPathError {
+    #[error("invalid external path")]
+    InvalidExternalPath,
+    #[error("invalid base64")]
+    InvalidBase64,
+    #[error("invalid utf-8")]
+    InvalidUtf8,
+}
+
+pub fn build_v2_external_media_proxy_path(input_url: &str) -> String {
+    format!(
+        "{V2_PREFIX}{}",
+        BASE64_URL_SAFE_NO_PAD.encode(input_url.as_bytes())
+    )
+}
+
+fn percent_encode_component(value: &str) -> String {
+    let mut out = String::with_capacity(value.len());
+    for byte in value.bytes() {
+        match byte {
+            b'A'..=b'Z'
+            | b'a'..=b'z'
+            | b'0'..=b'9'
+            | b'-'
+            | b'_'
+            | b'.'
+            | b'!'
+            | b'~'
+            | b'*'
+            | b'\''
+            | b'('
+            | b')' => out.push(byte as char),
+            _ => out.push_str(&format!("%{byte:02X}")),
+        }
+    }
+    out
+}
+
+pub fn build_external_media_proxy_path(input_url: &str) -> Result<String, ExternalPathError> {
+    let (scheme, remainder) = input_url
+        .split_once("://")
+        .ok_or(ExternalPathError::InvalidExternalPath)?;
+    if scheme.is_empty() || remainder.is_empty() {
+        return Err(ExternalPathError::InvalidExternalPath);
+    }
+    let (authority_and_path, query) = match remainder.split_once('?') {
+        Some((head, tail)) => (head, Some(tail)),
+        None => (remainder, None),
+    };
+    let (host, path) = match authority_and_path.split_once('/') {
+        Some((host, path)) => (host, path),
+        None => (authority_and_path, ""),
+    };
+    if host.is_empty() {
+        return Err(ExternalPathError::InvalidExternalPath);
+    }
+    let mut segments: Vec<String> = Vec::new();
+    if let Some(query) = query {
+        segments.push(percent_encode_component(&format!("?{query}")));
+    }
+    segments.push(scheme.to_owned());
+    segments.push(host.to_owned());
+    if !path.is_empty() {
+        segments.push(
+            path.split('/')
+                .map(percent_encode_component)
+                .collect::<Vec<_>>()
+                .join("/"),
+        );
+    }
+    Ok(segments.join("/"))
+}
+
+fn decode_v2(proxy_path: &str) -> Result<String, ExternalPathError> {
+    let encoded = proxy_path
+        .strip_prefix(V2_PREFIX)
+        .ok_or(ExternalPathError::InvalidExternalPath)?;
+    if encoded.is_empty() {
+        return Err(ExternalPathError::InvalidExternalPath);
+    }
+    let bytes = BASE64_URL_SAFE_NO_PAD
+        .decode(encoded)
+        .map_err(|_| ExternalPathError::InvalidBase64)?;
+    String::from_utf8(bytes).map_err(|_| ExternalPathError::InvalidUtf8)
+}
+
+fn hex_val(c: u8) -> Option<u8> {
+    match c {
+        b'0'..=b'9' => Some(c - b'0'),
+        b'a'..=b'f' => Some(c - b'a' + 10),
+        b'A'..=b'F' => Some(c - b'A' + 10),
+        _ => None,
+    }
+}
+
+pub fn percent_decode(input: &str, plus_as_space: bool) -> Vec<u8> {
+    let bytes = input.as_bytes();
+    let mut out = Vec::with_capacity(bytes.len());
+    let mut i = 0;
+    while i < bytes.len() {
+        let ch = bytes[i];
+        if ch == b'%'
+            && i + 2 < bytes.len()
+            && let (Some(hi), Some(lo)) = (hex_val(bytes[i + 1]), hex_val(bytes[i + 2]))
+        {
+            out.push((hi << 4) | lo);
+            i += 3;
+            continue;
+        }
+        out.push(if plus_as_space && ch == b'+' {
+            b' '
+        } else {
+            ch
+        });
+        i += 1;
+    }
+    out
+}
+
+pub fn percent_decode_string(input: &str, plus_as_space: bool) -> String {
+    String::from_utf8_lossy(&percent_decode(input, plus_as_space)).into_owned()
+}
+
+fn legacy_protocol_index(parts: &[&str]) -> Option<usize> {
+    for (index, part) in parts.iter().enumerate() {
+        if part.is_empty() {
+            continue;
+        }
+        if index == 0 && part.contains("%3D") {
+            continue;
+        }
+        let mut chars = part.bytes();
+        let first = chars.next()?;
+        if !first.is_ascii_alphabetic() {
+            continue;
+        }
+        if chars.all(|c| c.is_ascii_alphanumeric() || matches!(c, b'+' | b'.' | b'-')) {
+            return Some(index);
+        }
+    }
+    None
+}
+
+fn reconstruct_legacy(proxy_path: &str) -> Result<String, ExternalPathError> {
+    let parts: Vec<&str> = proxy_path.split('/').collect();
+    let protocol_index =
+        legacy_protocol_index(&parts).ok_or(ExternalPathError::InvalidExternalPath)?;
+    if protocol_index + 1 >= parts.len() {
+        return Err(ExternalPathError::InvalidExternalPath);
+    }
+    let protocol = parts[protocol_index];
+    let host_port = percent_decode_string(parts[protocol_index + 1], false);
+    let query_raw = parts[..protocol_index].join("/");
+    let path_raw = parts[protocol_index + 2..].join("/");
+    let query = percent_decode_string(&query_raw, false);
+    let path = percent_decode_string(&path_raw, false);
+    let normalized_query = query.strip_prefix('?').unwrap_or(&query);
+    Ok(format!(
+        "{protocol}://{host_port}/{path}{}{normalized_query}",
+        if normalized_query.is_empty() { "" } else { "?" }
+    ))
+}
+
+pub fn reconstruct_original_url(proxy_path: &str) -> Result<String, ExternalPathError> {
+    if proxy_path.starts_with(V2_PREFIX) {
+        decode_v2(proxy_path)
+    } else {
+        reconstruct_legacy(proxy_path)
+    }
+}
+
+type HmacSha256 = hmac::Hmac<sha2::Sha256>;
+
+pub fn create_signature(input: &str, secret: &[u8]) -> String {
+    use hmac::{KeyInit, Mac};
+    let mut mac = HmacSha256::new_from_slice(secret).expect("HMAC accepts any key length");
+    mac.update(input.as_bytes());
+    BASE64_URL_SAFE_NO_PAD.encode(mac.finalize().into_bytes())
+}
+
+pub fn build_external_media_proxy_url(
+    public_endpoint: &str,
+    input_url: &str,
+    secret: &[u8],
+) -> Option<String> {
+    let path = build_external_media_proxy_path(input_url).ok()?;
+    let signature = create_signature(&path, secret);
+    Some(format!("{public_endpoint}/external/{signature}/{path}"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn builds_the_plain_path_shape() {
+        assert_eq!(
+            "https/static.klipy.com/ii/c8/28/HkAKKCzZ.webp",
+            build_external_media_proxy_path("https://static.klipy.com/ii/c8/28/HkAKKCzZ.webp")
+                .unwrap()
+        );
+    }
+
+    #[test]
+    fn builds_an_encoded_query_ahead_of_the_scheme() {
+        assert_eq!(
+            "%3Fv%3Dquery_param%26goes%3Dhere/https/static.klipy.com/ii/HkAKKCzZ.webp",
+            build_external_media_proxy_path(
+                "https://static.klipy.com/ii/HkAKKCzZ.webp?v=query_param&goes=here"
+            )
+            .unwrap()
+        );
+    }
+
+    #[test]
+    fn keeps_a_non_default_port() {
+        assert_eq!(
+            "https/example.com:8443/a.png",
+            build_external_media_proxy_path("https://example.com:8443/a.png").unwrap()
+        );
+    }
+
+    #[test]
+    fn round_trips_every_shape() {
+        for url in [
+            "https://static.klipy.com/ii/c8/28/HkAKKCzZ.webp",
+            "https://static.klipy.com/ii/HkAKKCzZ.webp?v=query_param&goes=here",
+            "https://example.com:8443/a.png",
+            "https://avatars.githubusercontent.com/u/241303489?v=4",
+            "http://example.com/plain.gif",
+            "https://example.com/file.png?a=1&b=2&c=3",
+        ] {
+            let path = build_external_media_proxy_path(url).unwrap();
+            assert_eq!(
+                url,
+                reconstruct_original_url(&path).unwrap(),
+                "round trip {url}"
+            );
+        }
+    }
+
+    #[test]
+    fn does_not_double_the_question_mark() {
+        let decoded = reconstruct_original_url("%3Fa%3D1/https/example.com/x.png").unwrap();
+        assert_eq!("https://example.com/x.png?a=1", decoded);
+        assert!(!decoded.contains("??"));
+    }
+
+    #[test]
+    fn still_accepts_a_query_without_a_leading_question_mark() {
+        assert_eq!(
+            "https://example.com/x.png?a=1",
+            reconstruct_original_url("a%3D1/https/example.com/x.png").unwrap()
+        );
+    }
+
+    #[test]
+    fn rejects_a_url_without_a_scheme() {
+        assert!(build_external_media_proxy_path("example.com/a.png").is_err());
+    }
+
+    #[test]
+    fn v2_path_roundtrip() {
+        let path = build_v2_external_media_proxy_path("https://example.com/a b.png?x=1");
+        let decoded = reconstruct_original_url(&path).unwrap();
+        assert_eq!("https://example.com/a b.png?x=1", decoded);
+    }
+}

fluxer_common/src/lib.rs

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
 pub mod config;
+pub mod external_media_path;
 pub mod geoip;

fluxer_gifs/Cargo.toml

@@ -7,6 +7,7 @@ edition.workspace = true
 license.workspace = true
 
 [dependencies]
+fluxer_common = { path = "../fluxer_common" }
 anyhow = "1.0.102"
 base64 = "0.22.1"
 fluxer-svc = { path = "../fluxer_svc", default-features = false }

fluxer_gifs/src/media_proxy.rs

@@ -1,12 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-use base64::prelude::*;
-use hmac::{Hmac, KeyInit, Mac};
-use sha2::Sha256;
 use url::Url;
 
-const V2_PATH_PREFIX: &str = "v2/";
-
 #[derive(Clone)]
 pub struct MediaProxyUrlBuilder {
     endpoint: String,
@@ -66,28 +61,14 @@ impl MediaProxyUrlBuilder {
             return Some(input_url.to_owned());
         }
 
-        let proxy_path = build_external_media_proxy_path(parsed.as_str());
-        let signature = create_signature(&proxy_path, &self.secret_key);
-        Some(format!(
-            "{}/external/{signature}/{proxy_path}",
-            self.endpoint
-        ))
+        fluxer_common::external_media_path::build_external_media_proxy_url(
+            &self.endpoint,
+            parsed.as_str(),
+            self.secret_key.as_bytes(),
+        )
     }
 }
 
-fn build_external_media_proxy_path(input_url: &str) -> String {
-    format!(
-        "{V2_PATH_PREFIX}{}",
-        BASE64_URL_SAFE_NO_PAD.encode(input_url)
-    )
-}
-
-fn create_signature(input: &str, secret: &str) -> String {
-    let mut mac = Hmac::<Sha256>::new_from_slice(secret.as_bytes()).expect("HMAC accepts any key");
-    mac.update(input.as_bytes());
-    BASE64_URL_SAFE_NO_PAD.encode(mac.finalize().into_bytes())
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -153,7 +134,7 @@ mod tests {
             .expect("proxy url");
 
         assert!(url.starts_with("https://media.example.test/external/"));
-        assert!(url.contains("/v2/"));
+        assert!(url.contains("/https/"));
         assert_eq!(
             builder.external_proxy_url("https://media.example.test/external/existing"),
             Some("https://media.example.test/external/existing".to_owned())

fluxer_media_proxy/Cargo.toml

@@ -18,6 +18,7 @@ name = "core"
 harness = false
 
 [dependencies]
+fluxer_common = { path = "../fluxer_common" }
 anyhow = "1.0.102"
 axum = {version = "0.8.9", default-features = false, features = ["http1", "json", "query", "tokio"]}
 base64 = "0.22.1"

fluxer_media_proxy/src/external_path.rs

@@ -1,257 +1,6 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
-use base64::prelude::*;
-use thiserror::Error;
-
-const V2_PREFIX: &str = "v2/";
-
-#[derive(Debug, Error, Eq, PartialEq)]
-pub enum ExternalPathError {
-    #[error("invalid external path")]
-    InvalidExternalPath,
-    #[error("invalid base64")]
-    InvalidBase64,
-    #[error("invalid utf-8")]
-    InvalidUtf8,
-}
-
-pub fn build_v2_external_media_proxy_path(input_url: &str) -> String {
-    format!(
-        "{V2_PREFIX}{}",
-        BASE64_URL_SAFE_NO_PAD.encode(input_url.as_bytes())
-    )
-}
-
-fn percent_encode_component(value: &str) -> String {
-    let mut out = String::with_capacity(value.len());
-    for byte in value.bytes() {
-        match byte {
-            b'A'..=b'Z'
-            | b'a'..=b'z'
-            | b'0'..=b'9'
-            | b'-'
-            | b'_'
-            | b'.'
-            | b'!'
-            | b'~'
-            | b'*'
-            | b'\''
-            | b'('
-            | b')' => out.push(byte as char),
-            _ => out.push_str(&format!("%{byte:02X}")),
-        }
-    }
-    out
-}
-
-pub fn build_external_media_proxy_path(input_url: &str) -> Result<String, ExternalPathError> {
-    let (scheme, remainder) = input_url
-        .split_once("://")
-        .ok_or(ExternalPathError::InvalidExternalPath)?;
-    if scheme.is_empty() || remainder.is_empty() {
-        return Err(ExternalPathError::InvalidExternalPath);
-    }
-    let (authority_and_path, query) = match remainder.split_once('?') {
-        Some((head, tail)) => (head, Some(tail)),
-        None => (remainder, None),
-    };
-    let (host, path) = match authority_and_path.split_once('/') {
-        Some((host, path)) => (host, path),
-        None => (authority_and_path, ""),
-    };
-    if host.is_empty() {
-        return Err(ExternalPathError::InvalidExternalPath);
-    }
-    let mut segments: Vec<String> = Vec::new();
-    if let Some(query) = query {
-        segments.push(percent_encode_component(&format!("?{query}")));
-    }
-    segments.push(scheme.to_owned());
-    segments.push(host.to_owned());
-    if !path.is_empty() {
-        segments.push(
-            path.split('/')
-                .map(percent_encode_component)
-                .collect::<Vec<_>>()
-                .join("/"),
-        );
-    }
-    Ok(segments.join("/"))
-}
-
-fn decode_v2(proxy_path: &str) -> Result<String, ExternalPathError> {
-    let encoded = proxy_path
-        .strip_prefix(V2_PREFIX)
-        .ok_or(ExternalPathError::InvalidExternalPath)?;
-    if encoded.is_empty() {
-        return Err(ExternalPathError::InvalidExternalPath);
-    }
-    let bytes = BASE64_URL_SAFE_NO_PAD
-        .decode(encoded)
-        .map_err(|_| ExternalPathError::InvalidBase64)?;
-    String::from_utf8(bytes).map_err(|_| ExternalPathError::InvalidUtf8)
-}
-
-fn hex_val(c: u8) -> Option<u8> {
-    match c {
-        b'0'..=b'9' => Some(c - b'0'),
-        b'a'..=b'f' => Some(c - b'a' + 10),
-        b'A'..=b'F' => Some(c - b'A' + 10),
-        _ => None,
-    }
-}
-
-pub fn percent_decode(input: &str, plus_as_space: bool) -> Vec<u8> {
-    let bytes = input.as_bytes();
-    let mut out = Vec::with_capacity(bytes.len());
-    let mut i = 0;
-    while i < bytes.len() {
-        let ch = bytes[i];
-        if ch == b'%'
-            && i + 2 < bytes.len()
-            && let (Some(hi), Some(lo)) = (hex_val(bytes[i + 1]), hex_val(bytes[i + 2]))
-        {
-            out.push((hi << 4) | lo);
-            i += 3;
-            continue;
-        }
-        out.push(if plus_as_space && ch == b'+' {
-            b' '
-        } else {
-            ch
-        });
-        i += 1;
-    }
-    out
-}
-
-pub fn percent_decode_string(input: &str, plus_as_space: bool) -> String {
-    String::from_utf8_lossy(&percent_decode(input, plus_as_space)).into_owned()
-}
-
-fn legacy_protocol_index(parts: &[&str]) -> Option<usize> {
-    for (index, part) in parts.iter().enumerate() {
-        if part.is_empty() {
-            continue;
-        }
-        if index == 0 && part.contains("%3D") {
-            continue;
-        }
-        let mut chars = part.bytes();
-        let first = chars.next()?;
-        if !first.is_ascii_alphabetic() {
-            continue;
-        }
-        if chars.all(|c| c.is_ascii_alphanumeric() || matches!(c, b'+' | b'.' | b'-')) {
-            return Some(index);
-        }
-    }
-    None
-}
-
-fn reconstruct_legacy(proxy_path: &str) -> Result<String, ExternalPathError> {
-    let parts: Vec<&str> = proxy_path.split('/').collect();
-    let protocol_index =
-        legacy_protocol_index(&parts).ok_or(ExternalPathError::InvalidExternalPath)?;
-    if protocol_index + 1 >= parts.len() {
-        return Err(ExternalPathError::InvalidExternalPath);
-    }
-    let protocol = parts[protocol_index];
-    let host_port = percent_decode_string(parts[protocol_index + 1], false);
-    let query_raw = parts[..protocol_index].join("/");
-    let path_raw = parts[protocol_index + 2..].join("/");
-    let query = percent_decode_string(&query_raw, false);
-    let path = percent_decode_string(&path_raw, false);
-    let normalized_query = query.strip_prefix('?').unwrap_or(&query);
-    Ok(format!(
-        "{protocol}://{host_port}/{path}{}{normalized_query}",
-        if normalized_query.is_empty() { "" } else { "?" }
-    ))
-}
-
-pub fn reconstruct_original_url(proxy_path: &str) -> Result<String, ExternalPathError> {
-    if proxy_path.starts_with(V2_PREFIX) {
-        decode_v2(proxy_path)
-    } else {
-        reconstruct_legacy(proxy_path)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn builds_the_plain_path_shape() {
-        assert_eq!(
-            "https/static.klipy.com/ii/c8/28/HkAKKCzZ.webp",
-            build_external_media_proxy_path("https://static.klipy.com/ii/c8/28/HkAKKCzZ.webp")
-                .unwrap()
-        );
-    }
-
-    #[test]
-    fn builds_an_encoded_query_ahead_of_the_scheme() {
-        assert_eq!(
-            "%3Fv%3Dquery_param%26goes%3Dhere/https/static.klipy.com/ii/HkAKKCzZ.webp",
-            build_external_media_proxy_path(
-                "https://static.klipy.com/ii/HkAKKCzZ.webp?v=query_param&goes=here"
-            )
-            .unwrap()
-        );
-    }
-
-    #[test]
-    fn keeps_a_non_default_port() {
-        assert_eq!(
-            "https/example.com:8443/a.png",
-            build_external_media_proxy_path("https://example.com:8443/a.png").unwrap()
-        );
-    }
-
-    #[test]
-    fn round_trips_every_shape() {
-        for url in [
-            "https://static.klipy.com/ii/c8/28/HkAKKCzZ.webp",
-            "https://static.klipy.com/ii/HkAKKCzZ.webp?v=query_param&goes=here",
-            "https://example.com:8443/a.png",
-            "https://avatars.githubusercontent.com/u/241303489?v=4",
-            "http://example.com/plain.gif",
-            "https://example.com/file.png?a=1&b=2&c=3",
-        ] {
-            let path = build_external_media_proxy_path(url).unwrap();
-            assert_eq!(
-                url,
-                reconstruct_original_url(&path).unwrap(),
-                "round trip {url}"
-            );
-        }
-    }
-
-    #[test]
-    fn does_not_double_the_question_mark() {
-        let decoded = reconstruct_original_url("%3Fa%3D1/https/example.com/x.png").unwrap();
-        assert_eq!("https://example.com/x.png?a=1", decoded);
-        assert!(!decoded.contains("??"));
-    }
-
-    #[test]
-    fn still_accepts_a_query_without_a_leading_question_mark() {
-        assert_eq!(
-            "https://example.com/x.png?a=1",
-            reconstruct_original_url("a%3D1/https/example.com/x.png").unwrap()
-        );
-    }
-
-    #[test]
-    fn rejects_a_url_without_a_scheme() {
-        assert!(build_external_media_proxy_path("example.com/a.png").is_err());
-    }
-
-    #[test]
-    fn v2_path_roundtrip() {
-        let path = build_v2_external_media_proxy_path("https://example.com/a b.png?x=1");
-        let decoded = reconstruct_original_url(&path).unwrap();
-        assert_eq!("https://example.com/a b.png?x=1", decoded);
-    }
-}
+pub use fluxer_common::external_media_path::{
+    ExternalPathError, build_external_media_proxy_path, build_v2_external_media_proxy_path,
+    percent_decode, percent_decode_string, reconstruct_original_url,
+};

fluxer_messages/Cargo.toml

@@ -5,6 +5,7 @@ edition.workspace = true
 license.workspace = true
 
 [dependencies]
+fluxer_common = { path = "../fluxer_common" }
 anyhow = "1.0.102"
 base64 = "0.22.1"
 chrono = { version = "0.4.45", default-features = false, features = ["serde"] }

fluxer_messages/src/shard_impl.rs

@@ -15,13 +15,11 @@ use crate::types::{
     MessageSnapshot, MessageStickerItem,
 };
 use crate::udt;
-use base64::Engine;
 use chrono::{DateTime, Utc};
 use fluxer_svc::shard::ShardService;
 use fluxer_svc::transport::NatsTransport;
 use fluxer_svc::{postgres, postgres::BigIntBound, postgres::KeyPart};
 use futures::stream::{self, StreamExt};
-use hmac::{Hmac, KeyInit, Mac};
 #[cfg(feature = "scylla")]
 use scylla::DeserializeRow;
 #[cfg(feature = "scylla")]
@@ -31,7 +29,6 @@ use scylla::response::query_result::QueryRowsResult;
 #[cfg(feature = "scylla")]
 use scylla::statement::prepared::PreparedStatement;
 use serde::Deserialize;
-use sha2::Sha256;
 use std::collections::{HashMap, HashSet};
 #[cfg(feature = "scylla")]
 use std::sync::Arc;
@@ -2796,23 +2793,12 @@ fn external_media_proxy_url(input_url: &str, options: &ResponseBuildOptions) ->
         Ok(url) => url,
         Err(_) => return input_url.to_owned(),
     };
-    let encoded =
-        base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(parsed_url.as_str().as_bytes());
-    let path = format!("v2/{encoded}");
-    let signature = create_signature(&path, &options.media_proxy_secret_key);
-    format!(
-        "{}/external/{}/{}",
+    fluxer_common::external_media_path::build_external_media_proxy_url(
         options.media_endpoint.trim_end_matches('/'),
-        signature,
-        path
+        parsed_url.as_str(),
+        options.media_proxy_secret_key.as_bytes(),
     )
-}
-
-fn create_signature(input: &str, secret: &str) -> String {
-    let mut mac =
-        Hmac::<Sha256>::new_from_slice(secret.as_bytes()).expect("hmac accepts any key size");
-    mac.update(input.as_bytes());
-    base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(mac.finalize().into_bytes())
+    .unwrap_or_else(|| input_url.to_owned())
 }
 
 fn dt_to_epoch_millis(dt: &DateTime<Utc>) -> i64 {

fluxer_unfurl/Cargo.toml

@@ -5,6 +5,7 @@ edition.workspace = true
 license.workspace = true
 
 [dependencies]
+fluxer_common = { path = "../fluxer_common" }
 ammonia = "4.1.2"
 anyhow = "1.0.102"
 base64 = "0.22.1"

fluxer_unfurl/src/media_proxy.rs

@@ -5,7 +5,6 @@ use std::time::Duration;
 use url::Url;
 
 const METADATA_TIMEOUT: Duration = Duration::from_secs(5);
-const EXTERNAL_PROXY_VERSION_PREFIX: &str = "v2/";
 
 pub struct MediaProxyClient {
     http_client: reqwest::Client,
@@ -120,30 +119,14 @@ impl MediaProxyClient {
             return Some(input_url.to_owned());
         }
         let parsed = Url::parse(input_url).ok()?;
-        let encoded = base64::Engine::encode(
-            &base64::engine::general_purpose::URL_SAFE_NO_PAD,
+        fluxer_common::external_media_path::build_external_media_proxy_url(
+            &self.public_endpoint,
             parsed.as_str(),
-        );
-        let path = format!("{EXTERNAL_PROXY_VERSION_PREFIX}{encoded}");
-        let signature = create_signature(&path, &self.secret_key);
-        Some(format!(
-            "{}/external/{}/{}",
-            self.public_endpoint, signature, path
-        ))
+            self.secret_key.as_bytes(),
+        )
     }
 }
 
-fn create_signature(input: &str, secret: &str) -> String {
-    use hmac::{Hmac, KeyInit, Mac};
-    let mut mac =
-        Hmac::<sha2::Sha256>::new_from_slice(secret.as_bytes()).expect("hmac accepts any key size");
-    mac.update(input.as_bytes());
-    base64::Engine::encode(
-        &base64::engine::general_purpose::URL_SAFE_NO_PAD,
-        mac.finalize().into_bytes(),
-    )
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -178,7 +161,7 @@ mod tests {
     }
 
     #[test]
-    fn external_proxy_url_uses_public_endpoint_and_v2_path() {
+    fn external_proxy_url_uses_public_endpoint_and_plain_path() {
         let client = reqwest::Client::new();
         let mp = MediaProxyClient::new_with_public_endpoint(
             "http://media-proxy:8080/",
@@ -191,15 +174,18 @@ mod tests {
             .expect("proxy url");
 
         assert!(proxy.starts_with("https://media.example.test/external/"));
-        assert!(proxy.contains("/v2/"));
+        assert!(proxy.contains("/https/"));
 
-        let encoded = proxy.rsplit('/').next().expect("encoded path segment");
-        let decoded =
-            base64::Engine::decode(&base64::engine::general_purpose::URL_SAFE_NO_PAD, encoded)
-                .expect("valid base64");
+        let path = proxy
+            .split_once("/external/")
+            .expect("external segment")
+            .1
+            .split_once('/')
+            .expect("signature segment")
+            .1;
         assert_eq!(
-            String::from_utf8(decoded).expect("utf8"),
-            "https://pbs.twimg.com/media/a.jpg?name=orig"
+            "https://pbs.twimg.com/media/a.jpg?name=orig",
+            fluxer_common::external_media_path::reconstruct_original_url(path).expect("decodes")
         );
         assert_eq!(
             mp.external_proxy_url("https://media.example.test/external/already"),

tools/dev/Cargo.toml

@@ -5,6 +5,7 @@ edition.workspace = true
 license.workspace = true
 
 [dependencies]
+fluxer_common = { path = "../../fluxer_common" }
 anyhow = "1.0.102"
 axum = "0.8.9"
 base64 = "0.22.1"

tools/dev/src/media_external.rs

@@ -1,10 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
 use anyhow::{Context, Result};
-use base64::{Engine, engine::general_purpose::URL_SAFE_NO_PAD};
 use clap::Args;
-use hmac::{Hmac, KeyInit, Mac};
-use sha2::Sha256;
 
 #[derive(Debug, Clone, Args)]
 pub struct SignExternalUrlArgs {
@@ -16,17 +13,12 @@ pub struct SignExternalUrlArgs {
 }
 
 pub fn sign_external_url(secret_key: &str, server_url: &str, upstream: &str) -> Result<String> {
-    let path = format!("v2/{}", URL_SAFE_NO_PAD.encode(upstream.as_bytes()));
-    let mut mac = Hmac::<Sha256>::new_from_slice(secret_key.as_bytes())
-        .context("failed to create HMAC signer")?;
-    mac.update(path.as_bytes());
-    let signature = URL_SAFE_NO_PAD.encode(mac.finalize().into_bytes());
-    Ok(format!(
-        "{}/external/{}/{}",
+    fluxer_common::external_media_path::build_external_media_proxy_url(
         server_url.trim_end_matches('/'),
-        signature,
-        path
-    ))
+        upstream,
+        secret_key.as_bytes(),
+    )
+    .context("failed to build the external media proxy url")
 }
 
 #[cfg(test)]
@@ -41,13 +33,20 @@ mod tests {
             "https://example.test/a b.jpg",
         )
         .unwrap();
-        let parts = signed.split('/').collect::<Vec<_>>();
         assert!(signed.starts_with("http://127.0.0.1:19110/external/"));
-        assert_eq!(parts[5], "v2");
+        assert!(signed.ends_with("/https/example.test/a%20b.jpg"));
         assert_eq!(
-            URL_SAFE_NO_PAD.decode(parts[6]).unwrap(),
-            b"https://example.test/a b.jpg"
+            "https://example.test/a b.jpg",
+            fluxer_common::external_media_path::reconstruct_original_url(
+                signed
+                    .split_once("/external/")
+                    .unwrap()
+                    .1
+                    .split_once('/')
+                    .unwrap()
+                    .1
+            )
+            .unwrap()
         );
-        assert_eq!(URL_SAFE_NO_PAD.decode(parts[4]).unwrap().len(), 32);
     }
 }