Cargo.toml

@@ -47,6 +47,11 @@ required-features = ["bin", "database-json", "library-beets", "library-beets-ssh
 name = "musichoard-edit"
 required-features = ["bin", "database-json"]
 
+[[example]]
+name = "musicbrainz-api---browse"
+path = "examples/musicbrainz_api/browse.rs"
+required-features = ["bin", "musicbrainz"]
+
 [[example]]
 name = "musicbrainz-api---lookup"
 path = "examples/musicbrainz_api/lookup.rs"

examples/musicbrainz_api/browse.rs

@@ -0,0 +1,98 @@
+use std::{thread, time};
+
+use musichoard::{
+    collection::musicbrainz::Mbid,
+    external::musicbrainz::{
+        api::{browse::BrowseReleaseGroupRequest, MusicBrainzClient, NextPage, PageSettings},
+        http::MusicBrainzHttp,
+    },
+};
+use structopt::StructOpt;
+use uuid::Uuid;
+
+const USER_AGENT: &str = concat!(
+    "MusicHoard---examples---musicbrainz-api---browse/",
+    env!("CARGO_PKG_VERSION"),
+    " ( musichoard@thenineworlds.net )"
+);
+
+#[derive(StructOpt)]
+struct Opt {
+    #[structopt(subcommand)]
+    entity: OptEntity,
+}
+
+#[derive(StructOpt)]
+enum OptEntity {
+    #[structopt(about = "Browse release groups")]
+    ReleaseGroup(OptReleaseGroup),
+}
+
+#[derive(StructOpt)]
+enum OptReleaseGroup {
+    #[structopt(about = "Browse release groups of an artist")]
+    Artist(OptMbid),
+}
+
+#[derive(StructOpt)]
+struct OptMbid {
+    #[structopt(help = "MBID of the entity")]
+    mbid: Uuid,
+}
+
+fn main() {
+    let opt = Opt::from_args();
+
+    println!("USER_AGENT: {USER_AGENT}");
+
+    let http = MusicBrainzHttp::new(USER_AGENT).expect("failed to create API client");
+    let mut client = MusicBrainzClient::new(http);
+
+    match opt.entity {
+        OptEntity::ReleaseGroup(opt_release_group) => match opt_release_group {
+            OptReleaseGroup::Artist(opt_mbid) => {
+                let mbid: Mbid = opt_mbid.mbid.into();
+                let request = BrowseReleaseGroupRequest::artist(&mbid);
+                let mut paging = PageSettings::with_max_limit();
+
+                let mut response_counts: Vec<usize> = Vec::new();
+
+                loop {
+                    let response = client
+                        .browse_release_group(&request, &paging)
+                        .expect("failed to make API call");
+
+                    for rg in response.release_groups.iter() {
+                        println!("{rg:?}\n");
+                    }
+
+                    let offset = response.page.release_group_offset;
+                    let count = response.release_groups.len();
+                    response_counts.push(count);
+                    let total = response.page.release_group_count;
+
+                    println!("Release group offset           : {offset}");
+                    println!("Release groups in this response: {count}");
+                    println!("Release groups in total        : {total}");
+
+                    match response.page.next_page_offset(count) {
+                        NextPage::Offset(next_offset) => paging.with_offset(next_offset),
+                        NextPage::Complete => break,
+                    }
+
+                    thread::sleep(time::Duration::from_secs(1));
+                }
+
+                println!(
+                    "Total: {}={} release groups",
+                    response_counts
+                        .iter()
+                        .map(|i| i.to_string())
+                        .collect::<Vec<_>>()
+                        .join("+"),
+                    response_counts.iter().sum::<usize>(),
+                );
+            }
+        },
+    }
+}

examples/musicbrainz_api/lookup.rs

@@ -1,5 +1,3 @@
-#![allow(non_snake_case)]
-
 use musichoard::{
     collection::musicbrainz::Mbid,
     external::musicbrainz::{
@@ -64,7 +62,7 @@ fn main() {
             }
 
             let response = client
-                .lookup_artist(request)
+                .lookup_artist(&request)
                 .expect("failed to make API call");
 
             println!("{response:#?}");
@@ -74,7 +72,7 @@ fn main() {
             let request = LookupReleaseGroupRequest::new(&mbid);
 
             let response = client
-                .lookup_release_group(request)
+                .lookup_release_group(&request)
                 .expect("failed to make API call");
 
             println!("{response:#?}");

examples/musicbrainz_api/search.rs

@@ -1,5 +1,3 @@
-#![allow(non_snake_case)]
-
 use std::{num::ParseIntError, str::FromStr};
 
 use musichoard::{
@@ -7,7 +5,7 @@ use musichoard::{
     external::musicbrainz::{
         api::{
             search::{SearchArtistRequest, SearchReleaseGroupRequest},
-            MusicBrainzClient,
+            MusicBrainzClient, PageSettings,
         },
         http::MusicBrainzHttp,
     },
@@ -108,8 +106,9 @@ fn main() {
 
             println!("Query: {query}");
 
+            let paging = PageSettings::default();
             let matches = client
-                .search_artist(query)
+                .search_artist(&query, &paging)
                 .expect("failed to make API call");
 
             println!("{matches:#?}");
@@ -140,8 +139,9 @@ fn main() {
 
             println!("Query: {query}");
 
+            let paging = PageSettings::default();
             let matches = client
-                .search_release_group(query)
+                .search_release_group(&query, &paging)
                 .expect("failed to make API call");
 
             println!("{matches:#?}");

src/external/musicbrainz/api/browse.rs

@@ -0,0 +1,178 @@
+use std::fmt;
+
+use serde::Deserialize;
+
+use crate::{
+    collection::musicbrainz::Mbid,
+    external::musicbrainz::{
+        api::{
+            ApiDisplay, Error, MbReleaseGroupMeta, MusicBrainzClient, NextPage, PageSettings,
+            SerdeMbReleaseGroupMeta, MB_BASE_URL,
+        },
+        IMusicBrainzHttp,
+    },
+};
+
+#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Eq)]
+#[serde(rename_all(deserialize = "kebab-case"))]
+pub struct BrowseReleaseGroupPage {
+    pub release_group_offset: usize,
+    pub release_group_count: usize,
+}
+
+impl BrowseReleaseGroupPage {
+    pub fn next_page_offset(&self, page_count: usize) -> NextPage {
+        NextPage::next_page_offset(
+            self.release_group_offset,
+            self.release_group_count,
+            page_count,
+        )
+    }
+}
+
+pub type SerdeBrowseReleaseGroupPage = BrowseReleaseGroupPage;
+
+impl<Http: IMusicBrainzHttp> MusicBrainzClient<Http> {
+    pub fn browse_release_group(
+        &mut self,
+        request: &BrowseReleaseGroupRequest,
+        paging: &PageSettings,
+    ) -> Result<BrowseReleaseGroupResponse, Error> {
+        let entity = &request.entity;
+        let mbid = request.mbid.uuid().as_hyphenated();
+        let page = ApiDisplay::format_page_settings(paging);
+
+        let url = format!("{MB_BASE_URL}/release-group?{entity}={mbid}{page}");
+
+        let response: DeserializeBrowseReleaseGroupResponse = self.http.get(&url)?;
+        Ok(response.into())
+    }
+}
+
+pub struct BrowseReleaseGroupRequest<'a> {
+    entity: BrowseReleaseGroupRequestEntity,
+    mbid: &'a Mbid,
+}
+
+enum BrowseReleaseGroupRequestEntity {
+    Artist,
+}
+
+impl fmt::Display for BrowseReleaseGroupRequestEntity {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            BrowseReleaseGroupRequestEntity::Artist => write!(f, "artist"),
+        }
+    }
+}
+
+impl<'a> BrowseReleaseGroupRequest<'a> {
+    pub fn artist(mbid: &'a Mbid) -> Self {
+        BrowseReleaseGroupRequest {
+            entity: BrowseReleaseGroupRequestEntity::Artist,
+            mbid,
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct BrowseReleaseGroupResponse {
+    pub release_groups: Vec<MbReleaseGroupMeta>,
+    pub page: BrowseReleaseGroupPage,
+}
+
+#[derive(Clone, Deserialize)]
+#[serde(rename_all(deserialize = "kebab-case"))]
+struct DeserializeBrowseReleaseGroupResponse {
+    release_groups: Option<Vec<SerdeMbReleaseGroupMeta>>,
+    #[serde(flatten)]
+    page: SerdeBrowseReleaseGroupPage,
+}
+
+impl From<DeserializeBrowseReleaseGroupResponse> for BrowseReleaseGroupResponse {
+    fn from(value: DeserializeBrowseReleaseGroupResponse) -> Self {
+        BrowseReleaseGroupResponse {
+            page: value.page,
+            release_groups: value
+                .release_groups
+                .map(|rgs| rgs.into_iter().map(Into::into).collect())
+                .unwrap_or_default(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use mockall::predicate;
+
+    use crate::{
+        collection::album::{AlbumPrimaryType, AlbumSecondaryType},
+        external::musicbrainz::{
+            api::{
+                tests::next_page_test, SerdeAlbumDate, SerdeAlbumPrimaryType,
+                SerdeAlbumSecondaryType, SerdeMbid, MB_MAX_PAGE_LIMIT,
+            },
+            MockIMusicBrainzHttp,
+        },
+    };
+
+    use super::*;
+
+    #[test]
+    fn browse_release_group_next_page() {
+        let page = BrowseReleaseGroupPage {
+            release_group_offset: 5,
+            release_group_count: 45,
+        };
+
+        next_page_test(|val| page.next_page_offset(val));
+    }
+
+    #[test]
+    fn browse_release_group() {
+        let mbid = "00000000-0000-0000-0000-000000000000";
+        let mut http = MockIMusicBrainzHttp::new();
+
+        let de_release_group_offset = 24;
+        let de_release_group_count = 302;
+        let de_meta = SerdeMbReleaseGroupMeta {
+            id: SerdeMbid("11111111-1111-1111-1111-111111111111".try_into().unwrap()),
+            title: String::from("an album"),
+            first_release_date: SerdeAlbumDate((1986, 4).into()),
+            primary_type: Some(SerdeAlbumPrimaryType(AlbumPrimaryType::Album)),
+            secondary_types: Some(vec![SerdeAlbumSecondaryType(
+                AlbumSecondaryType::Compilation,
+            )]),
+        };
+        let de_response = DeserializeBrowseReleaseGroupResponse {
+            page: SerdeBrowseReleaseGroupPage {
+                release_group_offset: de_release_group_offset,
+                release_group_count: de_release_group_count,
+            },
+            release_groups: Some(vec![de_meta.clone()]),
+        };
+
+        let response = BrowseReleaseGroupResponse {
+            page: de_response.page,
+            release_groups: vec![de_meta.clone().into()],
+        };
+
+        let url = format!(
+            "https://musicbrainz.org/ws/2/release-group?artist={mbid}&limit={MB_MAX_PAGE_LIMIT}",
+        );
+        let expect_response = de_response.clone();
+        http.expect_get()
+            .times(1)
+            .with(predicate::eq(url))
+            .return_once(|_| Ok(expect_response));
+
+        let mut client = MusicBrainzClient::new(http);
+
+        let mbid: Mbid = mbid.try_into().unwrap();
+
+        let request = BrowseReleaseGroupRequest::artist(&mbid);
+        let paging = PageSettings::with_max_limit();
+        let result = client.browse_release_group(&request, &paging).unwrap();
+        assert_eq!(result, response);
+    }
+}

src/external/musicbrainz/api/lookup.rs

@@ -14,7 +14,7 @@ use super::{MbArtistMeta, MbReleaseGroupMeta, SerdeMbArtistMeta, SerdeMbReleaseG
 impl<Http: IMusicBrainzHttp> MusicBrainzClient<Http> {
     pub fn lookup_artist(
         &mut self,
-        request: LookupArtistRequest,
+        request: &LookupArtistRequest,
     ) -> Result<LookupArtistResponse, Error> {
         let mut include: Vec<String> = vec![];
 
@@ -35,7 +35,7 @@ impl<Http: IMusicBrainzHttp> MusicBrainzClient<Http> {
 
     pub fn lookup_release_group(
         &mut self,
-        request: LookupReleaseGroupRequest,
+        request: &LookupReleaseGroupRequest,
     ) -> Result<LookupReleaseGroupResponse, Error> {
         let url = format!(
             "{MB_BASE_URL}/release-group/{mbid}",
@@ -152,7 +152,7 @@ mod tests {
             id: SerdeMbid("11111111-1111-1111-1111-111111111111".try_into().unwrap()),
             title: String::from("an album"),
             first_release_date: SerdeAlbumDate((1986, 4).into()),
-            primary_type: SerdeAlbumPrimaryType(AlbumPrimaryType::Album),
+            primary_type: Some(SerdeAlbumPrimaryType(AlbumPrimaryType::Album)),
             secondary_types: Some(vec![SerdeAlbumSecondaryType(
                 AlbumSecondaryType::Compilation,
             )]),
@@ -177,7 +177,7 @@ mod tests {
         let mbid: Mbid = "00000000-0000-0000-0000-000000000000".try_into().unwrap();
         let mut request = LookupArtistRequest::new(&mbid);
         request.include_release_groups();
-        let result = client.lookup_artist(request).unwrap();
+        let result = client.lookup_artist(&request).unwrap();
 
         assert_eq!(result, response);
     }
@@ -192,7 +192,7 @@ mod tests {
             id: SerdeMbid("11111111-1111-1111-1111-111111111111".try_into().unwrap()),
             title: String::from("an album"),
             first_release_date: SerdeAlbumDate((1986, 4).into()),
-            primary_type: SerdeAlbumPrimaryType(AlbumPrimaryType::Album),
+            primary_type: Some(SerdeAlbumPrimaryType(AlbumPrimaryType::Album)),
             secondary_types: Some(vec![SerdeAlbumSecondaryType(
                 AlbumSecondaryType::Compilation,
             )]),
@@ -214,7 +214,7 @@ mod tests {
 
         let mbid: Mbid = "00000000-0000-0000-0000-000000000000".try_into().unwrap();
         let request = LookupReleaseGroupRequest::new(&mbid);
-        let result = client.lookup_release_group(request).unwrap();
+        let result = client.lookup_release_group(&request).unwrap();
 
         assert_eq!(result, response);
     }

src/external/musicbrainz/api/mod.rs

@@ -11,11 +11,14 @@ use crate::{
     external::musicbrainz::HttpError,
 };
 
+pub mod browse;
 pub mod lookup;
 pub mod search;
 
 const MB_BASE_URL: &str = "https://musicbrainz.org/ws/2";
 const MB_RATE_LIMIT_CODE: u16 = 503;
+const MB_MAX_PAGE_LIMIT: usize = 100;
+
 #[derive(Debug, PartialEq, Eq)]
 pub enum Error {
     /// The HTTP client failed.
@@ -58,6 +61,46 @@ impl<Http> MusicBrainzClient<Http> {
     }
 }
 
+#[derive(Default)]
+pub struct PageSettings {
+    pub limit: Option<usize>,
+    pub offset: Option<usize>,
+}
+
+impl PageSettings {
+    pub fn with_limit(limit: usize) -> Self {
+        PageSettings {
+            limit: Some(limit),
+            ..Default::default()
+        }
+    }
+
+    pub fn with_max_limit() -> Self {
+        Self::with_limit(MB_MAX_PAGE_LIMIT)
+    }
+
+    pub fn with_offset(&mut self, offset: usize) {
+        self.offset = Some(offset);
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum NextPage {
+    Offset(usize),
+    Complete,
+}
+
+impl NextPage {
+    pub fn next_page_offset(offset: usize, total_count: usize, page_count: usize) -> NextPage {
+        let next_offset = offset + page_count;
+        if next_offset < total_count {
+            NextPage::Offset(next_offset)
+        } else {
+            NextPage::Complete
+        }
+    }
+}
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct MbArtistMeta {
     pub id: Mbid,
@@ -91,7 +134,7 @@ pub struct MbReleaseGroupMeta {
     pub id: Mbid,
     pub title: String,
     pub first_release_date: AlbumDate,
-    pub primary_type: AlbumPrimaryType,
+    pub primary_type: Option<AlbumPrimaryType>,
     pub secondary_types: Option<Vec<AlbumSecondaryType>>,
 }
 
@@ -101,7 +144,7 @@ pub struct SerdeMbReleaseGroupMeta {
     id: SerdeMbid,
     title: String,
     first_release_date: SerdeAlbumDate,
-    primary_type: SerdeAlbumPrimaryType,
+    primary_type: Option<SerdeAlbumPrimaryType>,
     secondary_types: Option<Vec<SerdeAlbumSecondaryType>>,
 }
 
@@ -111,7 +154,7 @@ impl From<SerdeMbReleaseGroupMeta> for MbReleaseGroupMeta {
             id: value.id.into(),
             title: value.title,
             first_release_date: value.first_release_date.into(),
-            primary_type: value.primary_type.into(),
+            primary_type: value.primary_type.map(Into::into),
             secondary_types: value
                 .secondary_types
                 .map(|v| v.into_iter().map(Into::into).collect()),
@@ -122,6 +165,18 @@ impl From<SerdeMbReleaseGroupMeta> for MbReleaseGroupMeta {
 pub struct ApiDisplay;
 
 impl ApiDisplay {
+    fn format_page_settings(paging: &PageSettings) -> String {
+        let limit = paging
+            .limit
+            .map(|l| format!("&limit={l}"))
+            .unwrap_or_default();
+        let offset = paging
+            .offset
+            .map(|o| format!("&offset={o}"))
+            .unwrap_or_default();
+        format!("{limit}{offset}")
+    }
+
     fn format_album_date(date: &AlbumDate) -> String {
         match date.year {
             Some(year) => match date.month {
@@ -304,6 +359,45 @@ mod tests {
         assert!(!format!("{unk_err:?}").is_empty());
     }
 
+    pub fn next_page_test<Fn>(mut f: Fn)
+    where
+        Fn: FnMut(usize) -> NextPage,
+    {
+        let next = f(20);
+        assert_eq!(next, NextPage::Offset(25));
+
+        let next = f(40);
+        assert_eq!(next, NextPage::Complete);
+
+        let next = f(100);
+        assert_eq!(next, NextPage::Complete);
+    }
+
+    #[test]
+    fn next_page() {
+        next_page_test(|val| NextPage::next_page_offset(5, 45, val));
+    }
+
+    #[test]
+    fn format_page_settings() {
+        let paging = PageSettings::default();
+        assert_eq!(ApiDisplay::format_page_settings(&paging), "");
+
+        let paging = PageSettings::with_max_limit();
+        assert_eq!(ApiDisplay::format_page_settings(&paging), "&limit=100");
+
+        let mut paging = PageSettings::with_limit(45);
+        paging.with_offset(145);
+        assert_eq!(
+            ApiDisplay::format_page_settings(&paging),
+            "&limit=45&offset=145"
+        );
+
+        let mut paging = PageSettings::default();
+        paging.with_offset(26);
+        assert_eq!(ApiDisplay::format_page_settings(&paging), "&offset=26");
+    }
+
     #[test]
     fn format_album_date() {
         assert_eq!(

src/external/musicbrainz/api/search/artist.rs

@@ -3,7 +3,10 @@ use std::fmt;
 use serde::Deserialize;
 
 use crate::external::musicbrainz::api::{
-    search::query::{impl_term, EmptyQuery, EmptyQueryJoin, Query, QueryJoin},
+    search::{
+        query::{impl_term, EmptyQuery, EmptyQueryJoin, Query, QueryJoin},
+        SearchPage, SerdeSearchPage,
+    },
     MbArtistMeta, SerdeMbArtistMeta,
 };
 
@@ -26,18 +29,22 @@ impl_term!(string, SearchArtist<'a>, String, &'a str);
 #[derive(Debug, PartialEq, Eq)]
 pub struct SearchArtistResponse {
     pub artists: Vec<SearchArtistResponseArtist>,
+    pub page: SearchPage,
 }
 
 #[derive(Clone, Deserialize)]
 #[serde(rename_all(deserialize = "kebab-case"))]
 pub struct DeserializeSearchArtistResponse {
     artists: Vec<DeserializeSearchArtistResponseArtist>,
+    #[serde(flatten)]
+    page: SerdeSearchPage,
 }
 
 impl From<DeserializeSearchArtistResponse> for SearchArtistResponse {
     fn from(value: DeserializeSearchArtistResponse) -> Self {
         SearchArtistResponse {
             artists: value.artists.into_iter().map(Into::into).collect(),
+            page: value.page,
         }
     }
 }
@@ -70,13 +77,15 @@ mod tests {
     use mockall::predicate;
 
     use crate::external::musicbrainz::{
-        api::{MusicBrainzClient, SerdeMbid},
+        api::{MusicBrainzClient, PageSettings, SerdeMbid},
         MockIMusicBrainzHttp,
     };
 
     use super::*;
 
     fn de_response() -> DeserializeSearchArtistResponse {
+        let de_offset = 24;
+        let de_count = 124;
         let de_artist = DeserializeSearchArtistResponseArtist {
             score: 67,
             meta: SerdeMbArtistMeta {
@@ -88,6 +97,10 @@ mod tests {
         };
         DeserializeSearchArtistResponse {
             artists: vec![de_artist.clone()],
+            page: SerdeSearchPage {
+                offset: de_offset,
+                count: de_count,
+            },
         }
     }
 
@@ -101,6 +114,7 @@ mod tests {
                     meta: a.meta.into(),
                 })
                 .collect(),
+            page: de_response.page,
         }
     }
 
@@ -128,7 +142,8 @@ mod tests {
 
         let query = SearchArtistRequest::new().string(name);
 
-        let matches = client.search_artist(query).unwrap();
+        let paging = PageSettings::default();
+        let matches = client.search_artist(&query, &paging).unwrap();
         assert_eq!(matches, response);
     }
 }

src/external/musicbrainz/api/search/mod.rs

@@ -9,6 +9,7 @@ pub use release_group::{
 };
 
 use paste::paste;
+use serde::Deserialize;
 use url::form_urlencoded;
 
 use crate::external::musicbrainz::{
@@ -17,21 +18,40 @@ use crate::external::musicbrainz::{
             artist::DeserializeSearchArtistResponse,
             release_group::DeserializeSearchReleaseGroupResponse,
         },
-        Error, MusicBrainzClient, MB_BASE_URL,
+        ApiDisplay, Error, MusicBrainzClient, PageSettings, MB_BASE_URL,
     },
     IMusicBrainzHttp,
 };
 
+use super::NextPage;
+
+#[derive(Clone, Copy, Debug, Deserialize, PartialEq, Eq)]
+#[serde(rename_all(deserialize = "kebab-case"))]
+pub struct SearchPage {
+    pub offset: usize,
+    pub count: usize,
+}
+
+impl SearchPage {
+    pub fn next_page_offset(&self, page_count: usize) -> NextPage {
+        NextPage::next_page_offset(self.offset, self.count, page_count)
+    }
+}
+
+pub type SerdeSearchPage = SearchPage;
+
 macro_rules! impl_search_entity {
     ($name:ident, $entity:literal) => {
         paste! {
             pub fn [<search_ $name:snake>](
                 &mut self,
-                query: [<Search $name Request>]
+                query: &[<Search $name Request>],
+                paging: &PageSettings,
             ) -> Result<[<Search $name Response>], Error> {
                 let query: String =
                     form_urlencoded::byte_serialize(format!("{query}").as_bytes()).collect();
-                let url = format!("{MB_BASE_URL}/{entity}?query={query}", entity = $entity);
+                let page = ApiDisplay::format_page_settings(paging);
+                let url = format!("{MB_BASE_URL}/{entity}?query={query}{page}", entity = $entity);
 
                 let response: [<DeserializeSearch $name Response>] = self.http.get(&url)?;
                 Ok(response.into())
@@ -44,3 +64,20 @@ impl<Http: IMusicBrainzHttp> MusicBrainzClient<Http> {
     impl_search_entity!(Artist, "artist");
     impl_search_entity!(ReleaseGroup, "release-group");
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::external::musicbrainz::api::tests::next_page_test;
+
+    use super::*;
+
+    #[test]
+    fn search_next_page() {
+        let page = SearchPage {
+            offset: 5,
+            count: 45,
+        };
+
+        next_page_test(|val| page.next_page_offset(val));
+    }
+}

src/external/musicbrainz/api/search/release_group.rs

@@ -5,7 +5,10 @@ use serde::Deserialize;
 use crate::{
     collection::{album::AlbumDate, musicbrainz::Mbid},
     external::musicbrainz::api::{
-        search::query::{impl_term, EmptyQuery, EmptyQueryJoin, Query, QueryJoin},
+        search::{
+            query::{impl_term, EmptyQuery, EmptyQueryJoin, Query, QueryJoin},
+            SearchPage, SerdeSearchPage,
+        },
         ApiDisplay, MbReleaseGroupMeta, SerdeMbReleaseGroupMeta,
     },
 };
@@ -50,18 +53,22 @@ impl_term!(rgid, SearchReleaseGroup<'a>, Rgid, &'a Mbid);
 #[derive(Debug, PartialEq, Eq)]
 pub struct SearchReleaseGroupResponse {
     pub release_groups: Vec<SearchReleaseGroupResponseReleaseGroup>,
+    pub page: SearchPage,
 }
 
 #[derive(Clone, Deserialize)]
 #[serde(rename_all(deserialize = "kebab-case"))]
 pub struct DeserializeSearchReleaseGroupResponse {
     release_groups: Vec<DeserializeSearchReleaseGroupResponseReleaseGroup>,
+    #[serde(flatten)]
+    page: SerdeSearchPage,
 }
 
 impl From<DeserializeSearchReleaseGroupResponse> for SearchReleaseGroupResponse {
     fn from(value: DeserializeSearchReleaseGroupResponse) -> Self {
         SearchReleaseGroupResponse {
             release_groups: value.release_groups.into_iter().map(Into::into).collect(),
+            page: value.page,
         }
     }
 }
@@ -99,8 +106,8 @@ mod tests {
         collection::album::{AlbumPrimaryType, AlbumSecondaryType},
         external::musicbrainz::{
             api::{
-                MusicBrainzClient, SerdeAlbumDate, SerdeAlbumPrimaryType, SerdeAlbumSecondaryType,
+                MusicBrainzClient, PageSettings, SerdeAlbumDate, SerdeAlbumPrimaryType,
-                SerdeMbid,
+                SerdeAlbumSecondaryType, SerdeMbid,
             },
             MockIMusicBrainzHttp,
         },
@@ -109,18 +116,24 @@ mod tests {
     use super::*;
 
     fn de_response() -> DeserializeSearchReleaseGroupResponse {
+        let de_offset = 26;
+        let de_count = 126;
         let de_release_group = DeserializeSearchReleaseGroupResponseReleaseGroup {
             score: 67,
             meta: SerdeMbReleaseGroupMeta {
                 id: SerdeMbid("11111111-1111-1111-1111-111111111111".try_into().unwrap()),
                 title: String::from("an album"),
                 first_release_date: SerdeAlbumDate((1986, 4).into()),
-                primary_type: SerdeAlbumPrimaryType(AlbumPrimaryType::Album),
+                primary_type: Some(SerdeAlbumPrimaryType(AlbumPrimaryType::Album)),
                 secondary_types: Some(vec![SerdeAlbumSecondaryType(AlbumSecondaryType::Live)]),
             },
         };
         DeserializeSearchReleaseGroupResponse {
             release_groups: vec![de_release_group.clone()],
+            page: SerdeSearchPage {
+                offset: de_offset,
+                count: de_count,
+            },
         }
     }
 
@@ -134,6 +147,7 @@ mod tests {
                     meta: rg.meta.into(),
                 })
                 .collect(),
+            page: de_response.page,
         }
     }
 
@@ -161,7 +175,8 @@ mod tests {
 
         let query = SearchReleaseGroupRequest::new().string(title);
 
-        let matches = client.search_release_group(query).unwrap();
+        let paging = PageSettings::default();
+        let matches = client.search_release_group(&query, &paging).unwrap();
         assert_eq!(matches, response);
     }
 
@@ -198,7 +213,8 @@ mod tests {
             .and()
             .first_release_date(&date);
 
-        let matches = client.search_release_group(query).unwrap();
+        let paging = PageSettings::default();
+        let matches = client.search_release_group(&query, &paging).unwrap();
         assert_eq!(matches, response);
     }
 
@@ -226,7 +242,8 @@ mod tests {
 
         let query = SearchReleaseGroupRequest::new().rgid(&rgid);
 
-        let matches = client.search_release_group(query).unwrap();
+        let paging = PageSettings::default();
+        let matches = client.search_release_group(&query, &paging).unwrap();
         assert_eq!(matches, response);
     }
 }

src/tui/app/machine/browse_state.rs

@@ -1,7 +1,7 @@
 use crate::tui::app::{
     machine::{App, AppInner, AppMachine},
-    selection::{Delta, ListSelection},
+    selection::ListSelection,
-    AppPublicState, AppState, IAppInteractBrowse,
+    AppPublicState, AppState, Delta, IAppInteractBrowse,
 };
 
 pub struct BrowseState;

src/tui/app/machine/match_state.rs

@@ -9,8 +9,8 @@ use musichoard::collection::{
 use crate::tui::{
     app::{
         machine::{fetch_state::FetchState, input::Input, App, AppInner, AppMachine},
-        AlbumMatches, AppPublicState, AppState, ArtistMatches, IAppInteractMatch, ListOption,
+        AlbumMatches, AppPublicState, AppState, ArtistMatches, Delta, IAppInteractMatch,
-        MatchOption, MatchStateInfo, MatchStatePublic, WidgetState,
+        ListOption, MatchOption, MatchStateInfo, MatchStatePublic, WidgetState,
     },
     lib::interface::musicbrainz::api::{Lookup, Match},
 };
@@ -243,19 +243,19 @@ impl<'a> From<&'a mut MatchState> for AppPublicState<'a> {
 impl IAppInteractMatch for AppMachine<MatchState> {
     type APP = App;
 
-    fn prev_match(mut self) -> Self::APP {
+    fn decrement_match(mut self, delta: Delta) -> Self::APP {
         if let Some(index) = self.state.state.list.selected() {
-            let result = index.saturating_sub(1);
+            let result = index.saturating_sub(delta.as_usize(&self.state.state));
             self.state.state.list.select(Some(result));
         }
 
         self.into()
     }
 
-    fn next_match(mut self) -> Self::APP {
+    fn increment_match(mut self, delta: Delta) -> Self::APP {
         let index = self.state.state.list.selected().unwrap();
         let to = cmp::min(
-            index.saturating_add(1),
+            index.saturating_add(delta.as_usize(&self.state.state)),
             self.state.current.len().saturating_sub(1),
         );
         self.state.state.list.select(Some(to));
@@ -473,38 +473,38 @@ mod tests {
         assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state, widget_state);
 
-        let matches = matches.prev_match().unwrap_match();
+        let matches = matches.decrement_match(Delta::Line).unwrap_match();
 
         assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(0));
 
         let mut matches = matches;
         for ii in 1..len {
-            matches = matches.next_match().unwrap_match();
+            matches = matches.increment_match(Delta::Line).unwrap_match();
 
             assert_eq!(matches.state.current, matches_info);
             assert_eq!(matches.state.state.list.selected(), Some(ii));
         }
 
         // Next is CannotHaveMBID
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
 
         assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(len));
 
         // Next is ManualInputMbid
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
 
         assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(len + 1));
 
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
 
         assert_eq!(matches.state.current, matches_info);
         assert_eq!(matches.state.state.list.selected(), Some(len + 1));
 
         // Go prev_match first as selecting on manual input does not go back to fetch.
-        let matches = matches.prev_match().unwrap_match();
+        let matches = matches.decrement_match(Delta::Line).unwrap_match();
         matches.select().unwrap_fetch();
     }
 
@@ -619,10 +619,10 @@ mod tests {
             AppMachine::match_state(inner(music_hoard(vec![])), match_state(album_match()));
 
         // album_match has two matches which means that the fourth option should be manual input.
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
 
         let app = matches.select();
 
@@ -657,8 +657,8 @@ mod tests {
         );
 
         // There are no matches which means that the second option should be manual input.
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
 
         let mut app = matches.select();
         app = input_mbid(app);
@@ -691,8 +691,8 @@ mod tests {
         );
 
         // There are no matches which means that the second option should be manual input.
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
-        let matches = matches.next_match().unwrap_match();
+        let matches = matches.increment_match(Delta::Line).unwrap_match();
 
         let mut app = matches.select();
         app = input_mbid(app);

src/tui/app/mod.rs

@@ -2,7 +2,8 @@ mod machine;
 mod selection;
 
 pub use machine::App;
-pub use selection::{Category, Delta, Selection, WidgetState};
+use ratatui::widgets::ListState;
+pub use selection::{Category, Selection};
 
 use musichoard::collection::{
     album::AlbumMeta,
@@ -124,8 +125,8 @@ pub trait IAppEventFetch {
 pub trait IAppInteractMatch {
     type APP: IApp;
 
-    fn prev_match(self) -> Self::APP;
+    fn decrement_match(self, delta: Delta) -> Self::APP;
-    fn next_match(self) -> Self::APP;
+    fn increment_match(self, delta: Delta) -> Self::APP;
     fn select(self) -> Self::APP;
 
     fn abort(self) -> Self::APP;
@@ -159,6 +160,40 @@ pub trait IAppInteractError {
     fn dismiss_error(self) -> Self::APP;
 }
 
+#[derive(Clone, Debug, Default)]
+pub struct WidgetState {
+    pub list: ListState,
+    pub height: usize,
+}
+
+impl PartialEq for WidgetState {
+    fn eq(&self, other: &Self) -> bool {
+        self.list.selected().eq(&other.list.selected()) && self.height.eq(&other.height)
+    }
+}
+
+impl WidgetState {
+    #[must_use]
+    pub const fn with_selected(mut self, selected: Option<usize>) -> Self {
+        self.list = self.list.with_selected(selected);
+        self
+    }
+}
+
+pub enum Delta {
+    Line,
+    Page,
+}
+
+impl Delta {
+    fn as_usize(&self, state: &WidgetState) -> usize {
+        match self {
+            Delta::Line => 1,
+            Delta::Page => state.height.saturating_sub(1),
+        }
+    }
+}
+
 // It would be preferable to have a getter for each field separately. However, the selection field
 // needs to be mutably accessible requiring a mutable borrow of the entire struct if behind a trait.
 // This in turn complicates simultaneous field access since only a single mutable borrow is allowed.

src/tui/app/selection/album.rs

@@ -5,9 +5,12 @@ use musichoard::collection::{
     track::Track,
 };
 
-use crate::tui::app::selection::{
+use crate::tui::app::{
+    selection::{
         track::{KeySelectTrack, TrackSelection},
-    Delta, SelectionState, WidgetState,
+        SelectionState,
+    },
+    Delta, WidgetState,
 };
 
 #[derive(Clone, Debug, PartialEq)]

src/tui/app/selection/artist.rs

@@ -6,9 +6,12 @@ use musichoard::collection::{
     track::Track,
 };
 
-use crate::tui::app::selection::{
+use crate::tui::app::{
+    selection::{
         album::{AlbumSelection, KeySelectAlbum},
-    Delta, SelectionState, WidgetState,
+        SelectionState,
+    },
+    Delta, WidgetState,
 };
 
 #[derive(Clone, Debug, PartialEq)]

src/tui/app/selection/mod.rs

@@ -5,7 +5,10 @@ mod track;
 use musichoard::collection::{album::Album, artist::Artist, track::Track, Collection};
 use ratatui::widgets::ListState;
 
-use artist::{ArtistSelection, KeySelectArtist};
+use crate::tui::app::{
+    selection::artist::{ArtistSelection, KeySelectArtist},
+    Delta, WidgetState,
+};
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum Category {
@@ -24,40 +27,6 @@ pub struct SelectionState<'a, T> {
     pub index: usize,
 }
 
-#[derive(Clone, Debug, Default)]
-pub struct WidgetState {
-    pub list: ListState,
-    pub height: usize,
-}
-
-impl PartialEq for WidgetState {
-    fn eq(&self, other: &Self) -> bool {
-        self.list.selected().eq(&other.list.selected()) && self.height.eq(&other.height)
-    }
-}
-
-impl WidgetState {
-    #[must_use]
-    pub const fn with_selected(mut self, selected: Option<usize>) -> Self {
-        self.list = self.list.with_selected(selected);
-        self
-    }
-}
-
-pub enum Delta {
-    Line,
-    Page,
-}
-
-impl Delta {
-    fn as_usize(&self, state: &WidgetState) -> usize {
-        match self {
-            Delta::Line => 1,
-            Delta::Page => state.height.saturating_sub(1),
-        }
-    }
-}
-
 impl Selection {
     pub fn new(artists: &[Artist]) -> Self {
         Selection {

src/tui/app/selection/track.rs

@@ -2,7 +2,7 @@ use std::cmp;
 
 use musichoard::collection::track::{Track, TrackId, TrackNum};
 
-use crate::tui::app::selection::{Delta, SelectionState, WidgetState};
+use crate::tui::app::{selection::SelectionState, Delta, WidgetState};
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct TrackSelection {

src/tui/handler.rs

@@ -212,8 +212,10 @@ impl<APP: IApp> IEventHandlerPrivate<APP> for EventHandler {
             // Abort.
             KeyCode::Esc | KeyCode::Char('q') | KeyCode::Char('Q') => app.abort(),
             // Select.
-            KeyCode::Up => app.prev_match(),
+            KeyCode::Up => app.decrement_match(Delta::Line),
-            KeyCode::Down => app.next_match(),
+            KeyCode::Down => app.increment_match(Delta::Line),
+            KeyCode::PageUp => app.decrement_match(Delta::Page),
+            KeyCode::PageDown => app.increment_match(Delta::Page),
             KeyCode::Enter => app.select(),
             // Othey keys.
             _ => app.no_op(),

src/tui/lib/external/musicbrainz/api/mod.rs

@@ -18,7 +18,7 @@ use musichoard::{
                 SearchArtistRequest, SearchArtistResponseArtist, SearchReleaseGroupRequest,
                 SearchReleaseGroupResponseReleaseGroup,
             },
-            MusicBrainzClient,
+            MusicBrainzClient, PageSettings,
         },
         IMusicBrainzHttp,
     },
@@ -41,7 +41,7 @@ impl<Http: IMusicBrainzHttp> IMusicBrainz for MusicBrainz<Http> {
     fn lookup_artist(&mut self, mbid: &Mbid) -> Result<Lookup<ArtistMeta>, Error> {
         let request = LookupArtistRequest::new(mbid);
 
-        let mb_response = self.client.lookup_artist(request)?;
+        let mb_response = self.client.lookup_artist(&request)?;
 
         Ok(from_lookup_artist_response(mb_response))
     }
@@ -49,7 +49,7 @@ impl<Http: IMusicBrainzHttp> IMusicBrainz for MusicBrainz<Http> {
     fn lookup_release_group(&mut self, mbid: &Mbid) -> Result<Lookup<AlbumMeta>, Error> {
         let request = LookupReleaseGroupRequest::new(mbid);
 
-        let mb_response = self.client.lookup_release_group(request)?;
+        let mb_response = self.client.lookup_release_group(&request)?;
 
         Ok(from_lookup_release_group_response(mb_response))
     }
@@ -57,7 +57,8 @@ impl<Http: IMusicBrainzHttp> IMusicBrainz for MusicBrainz<Http> {
     fn search_artist(&mut self, artist: &ArtistMeta) -> Result<Vec<Match<ArtistMeta>>, Error> {
         let query = SearchArtistRequest::new().string(&artist.id.name);
 
-        let mb_response = self.client.search_artist(query)?;
+        let paging = PageSettings::default();
+        let mb_response = self.client.search_artist(&query, &paging)?;
 
         Ok(mb_response
             .artists
@@ -82,7 +83,8 @@ impl<Http: IMusicBrainzHttp> IMusicBrainz for MusicBrainz<Http> {
             .and()
             .release_group(&album.id.title);
 
-        let mb_response = self.client.search_release_group(query)?;
+        let paging = PageSettings::default();
+        let mb_response = self.client.search_release_group(&query, &paging)?;
 
         Ok(mb_response
             .release_groups
@@ -115,7 +117,7 @@ fn from_lookup_release_group_response(entity: LookupReleaseGroupResponse) -> Loo
             seq: AlbumSeq::default(),
             info: AlbumInfo {
                 musicbrainz: MbRefOption::Some(entity.meta.id.into()),
-                primary_type: Some(entity.meta.primary_type),
+                primary_type: entity.meta.primary_type,
                 secondary_types: entity.meta.secondary_types.unwrap_or_default(),
             },
         },
@@ -150,7 +152,7 @@ fn from_search_release_group_response_release_group(
             seq: AlbumSeq::default(),
             info: AlbumInfo {
                 musicbrainz: MbRefOption::Some(entity.meta.id.into()),
-                primary_type: Some(entity.meta.primary_type),
+                primary_type: entity.meta.primary_type,
                 secondary_types: entity.meta.secondary_types.unwrap_or_default(),
             },
         },