minecraft_java_rs_core/loader/
fabric.rs

1use tokio::sync::mpsc::Sender;
2
3use crate::error::LoaderError;
4use crate::launcher::events::LaunchEvent;
5use crate::launcher::options::LaunchOptions;
6use crate::models::loader::{FabricJson, FabricMeta, LoaderType};
7use crate::models::minecraft::AssetItem;
8use crate::net::downloader::{DownloadItem, Downloader};
9use crate::net::http::fetch_json;
10use crate::utils::paths::get_path_libraries;
11
12// ── Constants ─────────────────────────────────────────────────────────────────
13
14const FABRIC_META: &str = "https://meta.fabricmc.net/v2/versions";
15const FABRIC_PROFILE: &str =
16    "https://meta.fabricmc.net/v2/versions/loader/${version}/${build}/profile/json";
17
18const LEGACY_META: &str = "https://meta.legacyfabric.net/v2/versions";
19const LEGACY_PROFILE: &str =
20    "https://meta.legacyfabric.net/v2/versions/loader/${version}/${build}/profile/json";
21
22// ── Public types ──────────────────────────────────────────────────────────────
23
24#[derive(Debug, Clone, Copy, PartialEq, Eq)]
25pub enum FabricVariant {
26    Modern,
27    Legacy,
28}
29
30pub struct FabricMC {
31    variant: FabricVariant,
32}
33
34// ── Public API ────────────────────────────────────────────────────────────────
35
36impl FabricMC {
37    pub fn new(variant: FabricVariant) -> Self {
38        Self { variant }
39    }
40
41    pub fn loader_type(&self) -> LoaderType {
42        match self.variant {
43            FabricVariant::Modern => LoaderType::Fabric,
44            FabricVariant::Legacy => LoaderType::LegacyFabric,
45        }
46    }
47
48    /// Fetch the Fabric/LegacyFabric loader profile JSON for the given Minecraft version.
49    ///
50    /// `build` can be `"latest"`, `"recommended"` (treated same as latest for Fabric),
51    /// or an exact version string.
52    pub async fn download_json(
53        &self,
54        mc_version: &str,
55        build: &str,
56        client: &reqwest::Client,
57    ) -> Result<FabricJson, LoaderError> {
58        let (meta_url, profile_template) = match self.variant {
59            FabricVariant::Modern => (FABRIC_META, FABRIC_PROFILE),
60            FabricVariant::Legacy => (LEGACY_META, LEGACY_PROFILE),
61        };
62
63        let meta: FabricMeta = fetch_json(client, meta_url)
64            .await
65            .map_err(LoaderError::ApiError)?;
66
67        // Validate the MC version is supported.
68        let version_name = match self.variant {
69            FabricVariant::Modern => "FabricMC",
70            FabricVariant::Legacy => "LegacyFabric",
71        };
72        if !meta.game.iter().any(|g| g.version == mc_version) {
73            return Err(LoaderError::VersionNotFound(format!(
74                "{version_name} doesn't support Minecraft {mc_version}"
75            )));
76        }
77
78        // Resolve build.
79        let build_ver = if matches!(build, "latest" | "recommended") {
80            meta.loader
81                .first()
82                .map(|b| b.version.clone())
83                .ok_or_else(|| LoaderError::VersionNotFound(format!("No {version_name} builds available")))?
84        } else {
85            meta.loader
86                .iter()
87                .find(|b| b.version == build)
88                .map(|b| b.version.clone())
89                .ok_or_else(|| {
90                    let available: Vec<_> = meta.loader.iter().map(|b| b.version.as_str()).collect();
91                    LoaderError::VersionNotFound(format!(
92                        "{version_name} build {build} not found. Available: {}",
93                        available.join(", ")
94                    ))
95                })?
96        };
97
98        let profile_url = profile_template
99            .replace("${version}", mc_version)
100            .replace("${build}", &build_ver);
101
102        let json: FabricJson = fetch_json(client, &profile_url)
103            .await
104            .map_err(LoaderError::ApiError)?;
105
106        Ok(json)
107    }
108
109    /// Download any libraries from `fabric_json` that are not yet on disk.
110    ///
111    /// Emits `LaunchEvent::Check` for each library processed.
112    /// Returns `Vec<AssetItem>` covering every library (for bundle-integrity tracking).
113    pub async fn download_libraries(
114        &self,
115        options: &LaunchOptions,
116        fabric_json: &FabricJson,
117        _client: &reqwest::Client,
118        event_tx: &Sender<LaunchEvent>,
119    ) -> Result<Vec<AssetItem>, LoaderError> {
120        let libs = &fabric_json.libraries;
121        let total = libs.len();
122        let mut items: Vec<AssetItem> = Vec::with_capacity(total);
123        let mut pending: Vec<DownloadItem> = Vec::new();
124
125        for (idx, lib) in libs.iter().enumerate() {
126            let _ = event_tx
127                .send(LaunchEvent::Check {
128                    current: idx + 1,
129                    total,
130                    kind: "libraries".into(),
131                })
132                .await;
133
134            // Skip libraries with OS rules — same as the JS loader.
135            if lib.rules.is_some() {
136                continue;
137            }
138
139            let lib_info = match get_path_libraries(&lib.name, None, None) {
140                Ok(i) => i,
141                Err(_) => continue,
142            };
143
144            let loader_name = match self.variant {
145                FabricVariant::Modern => "fabric",
146                FabricVariant::Legacy => "legacyfabric",
147            };
148            let folder = options
149                .loader_dir(loader_name)
150                .join("libraries")
151                .join(&lib_info.path);
152            let dest = folder.join(&lib_info.name);
153
154            let url = resolve_lib_url(lib, &lib_info.path, &lib_info.name);
155
156            items.push(AssetItem::Asset {
157                path: dest.to_string_lossy().into_owned(),
158                sha1: lib
159                    .downloads
160                    .as_ref()
161                    .and_then(|d| d.artifact.as_ref())
162                    .and_then(|a| a.sha1.clone())
163                    .unwrap_or_default(),
164                size: lib
165                    .downloads
166                    .as_ref()
167                    .and_then(|d| d.artifact.as_ref())
168                    .and_then(|a| a.size)
169                    .unwrap_or(0),
170                url: url.clone(),
171            });
172
173            if !dest.exists() {
174                pending.push(DownloadItem {
175                    url,
176                    path: dest,
177                    folder,
178                    name: lib_info.name,
179                    size: 0,
180                    r#type: Some("libraries".into()),
181                    sha1: None,
182                });
183            }
184        }
185
186        if !pending.is_empty() {
187            let downloader = Downloader::new(options.timeout_secs, options.download_concurrency);
188            downloader
189                .download_multiple(pending, event_tx.clone())
190                .await
191                .map_err(|e| LoaderError::Io(std::io::Error::new(std::io::ErrorKind::Other, e.to_string())))?;
192        }
193
194        Ok(items)
195    }
196}
197
198// ── Helpers ───────────────────────────────────────────────────────────────────
199
200pub(crate) fn resolve_lib_url(
201    lib: &crate::models::loader::LoaderLibrary,
202    rel_path: &str,
203    name: &str,
204) -> String {
205    // Prefer explicit download URL from the downloads section.
206    if let Some(url) = lib
207        .downloads
208        .as_ref()
209        .and_then(|d| d.artifact.as_ref())
210        .map(|a| a.url.as_str())
211    {
212        return url.to_owned();
213    }
214
215    // Build URL from the base Maven repo URL.
216    let base = lib
217        .url
218        .as_deref()
219        .unwrap_or("https://repo1.maven.org/maven2/");
220    let base = base.trim_end_matches('/');
221    format!("{base}/{rel_path}/{name}")
222}
223
224// ── Tests ─────────────────────────────────────────────────────────────────────
225
226#[cfg(test)]
227mod tests {
228    use super::*;
229
230    #[test]
231    fn fabric_variant_modern_and_legacy_differ() {
232        assert_ne!(FabricVariant::Modern, FabricVariant::Legacy);
233    }
234
235    #[test]
236    fn resolve_lib_url_uses_downloads_url_when_present() {
237        use crate::models::loader::{LoaderArtifact, LoaderLibraryDownloads};
238        let lib = crate::models::loader::LoaderLibrary {
239            name: "a:b:1.0".into(),
240            url: Some("https://repo.example.com/".into()),
241            downloads: Some(LoaderLibraryDownloads {
242                artifact: Some(LoaderArtifact {
243                    sha1: None,
244                    size: None,
245                    path: None,
246                    url: "https://direct.example.com/b-1.0.jar".into(),
247                }),
248            }),
249            rules: None,
250            clientreq: None,
251        };
252        let url = resolve_lib_url(&lib, "a/b/1.0", "b-1.0.jar");
253        assert_eq!(url, "https://direct.example.com/b-1.0.jar");
254    }
255
256    #[test]
257    fn resolve_lib_url_constructs_from_base_url() {
258        let lib = crate::models::loader::LoaderLibrary {
259            name: "a:b:1.0".into(),
260            url: Some("https://maven.fabricmc.net/".into()),
261            downloads: None,
262            rules: None,
263            clientreq: None,
264        };
265        let url = resolve_lib_url(&lib, "a/b/1.0", "b-1.0.jar");
266        assert_eq!(url, "https://maven.fabricmc.net/a/b/1.0/b-1.0.jar");
267    }
268
269    #[test]
270    fn resolve_lib_url_falls_back_to_maven_central() {
271        let lib = crate::models::loader::LoaderLibrary {
272            name: "a:b:1.0".into(),
273            url: None,
274            downloads: None,
275            rules: None,
276            clientreq: None,
277        };
278        let url = resolve_lib_url(&lib, "a/b/1.0", "b-1.0.jar");
279        assert!(url.contains("repo1.maven.org"));
280        assert!(url.contains("b-1.0.jar"));
281    }
282}
minecraft_java_rs_core/loader/fabric.rs

minecraft_java_rs_core/loader/
fabric.rs
