reusable pagination types

crates/service/web/storyteller_web/src/http_server/common_responses/mod.rs

@@ -1 +1,3 @@
+pub mod pagination_cursors;
+pub mod pagination_page;
 pub mod user_details_lite;

crates/service/web/storyteller_web/src/http_server/common_responses/pagination_cursors.rs

@@ -0,0 +1,53 @@
+/// Pagination by cursors
+/// These types of pagination are for "infinite scrolling", which do not reveal a number of pages.
+/// This is good so that investors and competitors cannot reveal how many database records we have.
+/// This is typically used for "discovery" type pages, not user profiles.
+///
+/// See `PaginationPage` for the other type of pagination.
+#[derive(Serialize)]
+pub struct PaginationCursors {
+
+  /// The "next" cursor.
+  /// This is an opaque (typically even encrypted) handle.
+  pub maybe_next: Option<String>,
+
+  /// The "previous" cursor.
+  /// This is an opaque (typically even encrypted) handle.
+  pub maybe_previous: Option<String>,
+
+  /// Details whether we're walking forward or backward.
+  pub cursor_is_reversed: bool,
+}
+
+#[cfg(test)]
+mod tests {
+  use crate::http_server::common_responses::pagination_cursors::PaginationCursors;
+
+  #[test]
+  fn test_serialize_empty_json() {
+    // Make sure this interface doesn't change.
+    let pagination = PaginationCursors {
+      maybe_next: None,
+      maybe_previous: None,
+      cursor_is_reversed: false,
+    };
+
+    let json = serde_json::to_string(&pagination).expect("serialization");
+
+    assert_eq!(json, "{\"maybe_next\":null,\"maybe_previous\":null,\"cursor_is_reversed\":false}")
+  }
+
+  #[test]
+  fn test_serialize_full_json() {
+    // Make sure this interface doesn't change.
+    let pagination = PaginationCursors {
+      maybe_next: Some("foo".to_string()),
+      maybe_previous: Some("bar".to_string()),
+      cursor_is_reversed: true,
+    };
+
+    let json = serde_json::to_string(&pagination).expect("serialization");
+
+    assert_eq!(json, "{\"maybe_next\":\"foo\",\"maybe_previous\":\"bar\",\"cursor_is_reversed\":true}")
+  }
+}

crates/service/web/storyteller_web/src/http_server/common_responses/pagination_page.rs

@@ -0,0 +1,33 @@
+/// Pagination by page id
+/// This type of pagination is by "page id" and "page count".
+/// This should never be used to walk the entire public database as competitors and investors
+/// can use it to glean information about the scale of our service.
+/// This is best used for user profiles and scoped down results.
+///
+/// See `PaginationCursors` for the other type of pagination.
+#[derive(Serialize)]
+pub struct PaginationPage {
+  /// The current page number
+  pub current: u64,
+
+  /// How many pages there are in total
+  pub total_page_count: u64,
+}
+
+#[cfg(test)]
+mod tests {
+  use crate::http_server::common_responses::pagination_page::PaginationPage;
+
+  #[test]
+  fn test_serialize() {
+    let pagination = PaginationPage {
+      current: 5,
+      total_page_count: 123,
+
+    };
+
+    let json = serde_json::to_string(&pagination).expect("serialization");
+
+    assert_eq!(json, "{\"current\":5,\"total_page_count\":123}")
+  }
+}

crates/service/web/storyteller_web/src/http_server/endpoints/media_files/list_media_files_for_user.rs

@@ -15,6 +15,7 @@ use enums::common::visibility::Visibility;
 use mysql_queries::queries::media_files::list_media_files_for_user::{list_media_files_for_user, ListMediaFileForUserArgs, ViewAs};
 use tokens::tokens::media_files::MediaFileToken;
 
+use crate::http_server::common_responses::pagination_cursors::PaginationCursors;
 use crate::http_server::web_utils::response_error_helpers::to_simple_json_error;
 use crate::server_state::ServerState;
 
@@ -36,8 +37,7 @@ pub struct QueryParams {
 pub struct SuccessResponse {
   pub success: bool,
   pub results: Vec<MediaFileListItem>,
-  pub cursor_next: Option<String>,
-  pub cursor_previous: Option<String>,
+  pub pagination: PaginationCursors,
 }
 
 #[derive(Serialize)]
@@ -202,8 +202,11 @@ pub async fn list_media_files_for_user_handler(
   let response = SuccessResponse {
     success: true,
     results,
-    cursor_next,
-    cursor_previous,
+    pagination: PaginationCursors {
+      maybe_next: cursor_next,
+      maybe_previous: cursor_previous,
+      cursor_is_reversed,
+    }
   };
 
   let body = serde_json::to_string(&response)