Partially implement BEP 53

This enables `--select-only 1,2,3` which gets appended to the magnet
link as `&so=1,2,3`.

It's a partial implementation because we're missing support for file
ranges ie `--select-only 4-6`

type: added
fixes:
- https://github.com/casey/intermodal/issues/245

CHANGELOG.md

@@ -2,9 +2,10 @@ Changelog
 =========
 
 
-UNRELEASED - 2020-04-12
+UNRELEASED - 2020-04-13
 -----------------------
-- :books: [`xxxxxxxxxxxx`](https://github.com/casey/intermodal/commits/master) Add table of packages to readme ([#372](https://github.com/casey/intermodal/pull/372)) - Fixes [#369](https://github.com/casey/intermodal/issues/369) - _Casey Rodarmor <casey@rodarmor.com>_
+- :sparkles: [`xxxxxxxxxxxx`](https://github.com/casey/intermodal/commits/master) Partially implement BEP 53 - Fixes [#245](https://github.com/casey/intermodal/issues/245) - _strickinato <aaronstrick@gmail.com>_
+- :books: [`6185d6c8a27c`](https://github.com/casey/intermodal/commit/6185d6c8a27c0d603f0434e98000c8e4a868dcc8) Add table of packages to readme ([#372](https://github.com/casey/intermodal/pull/372)) - Fixes [#369](https://github.com/casey/intermodal/issues/369) - _Casey Rodarmor <casey@rodarmor.com>_
 - :wrench: [`ddf097c83690`](https://github.com/casey/intermodal/commit/ddf097c8369002748992165f81e9a1bdbe6eff98) Fix `publish` recipe ([#368](https://github.com/casey/intermodal/pull/368)) - _Casey Rodarmor <casey@rodarmor.com>_
 
 

book/src/commands/imdl-torrent-link.md

@@ -14,8 +14,12 @@ FLAGS:
     -V, --version    Print version number.
 
 OPTIONS:
-    -i, --input <METAINFO>    Generate magnet link from metainfo at `PATH`. If
+    -s, --select-only <INDICES>...
-                              `PATH` is `-`, read metainfo from standard input.
+            Specify files that torrent clients select for download. Values are
-    -p, --peer <PEER>...      Add `PEER` to magnet link.
+            indices into the info.files list. e.g. `--select-only 1,2,3`
+    -i, --input <METAINFO>
+            Generate magnet link from metainfo at `PATH`. If `PATH` is `-`, read
+            metainfo from standard input.
+    -p, --peer <PEER>...              Add `PEER` to magnet link.
 
 ```

completions/imdl.bash

@@ -245,7 +245,7 @@ _imdl() {
             return 0
             ;;
         imdl__torrent__link)
-            opts=" -O -h -V -i -p  --open --help --version --input --peer  "
+            opts=" -O -h -V -i -p -s  --open --help --version --input --peer --select-only  "
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 3 ]] ; then
                 COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                 return 0
@@ -268,6 +268,14 @@ _imdl() {
                     COMPREPLY=($(compgen -f "${cur}"))
                     return 0
                     ;;
+                --select-only)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
+                    -s)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
                 *)
                     COMPREPLY=()
                     ;;

completions/imdl.elvish

@@ -124,8 +124,10 @@ Sort in ascending order by size, break ties in descending path order:
             cand --input 'Generate magnet link from metainfo at `PATH`. If `PATH` is `-`, read metainfo from standard input.'
             cand -p 'Add `PEER` to magnet link.'
             cand --peer 'Add `PEER` to magnet link.'
-            cand -O 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows'
+            cand -s 'Select files to download. Values are indices into the `info.files` list, e.g. `--select-only 1,2,3`.'
-            cand --open 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows'
+            cand --select-only 'Select files to download. Values are indices into the `info.files` list, e.g. `--select-only 1,2,3`.'
+            cand -O 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows.'
+            cand --open 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows.'
             cand -h 'Print help message.'
             cand --help 'Print help message.'
             cand -V 'Print version number.'

completions/imdl.fish

@@ -69,7 +69,8 @@ complete -c imdl -n "__fish_seen_subcommand_from create" -l help -d 'Print help
 complete -c imdl -n "__fish_seen_subcommand_from create" -s V -l version -d 'Print version number.'
 complete -c imdl -n "__fish_seen_subcommand_from link" -s i -l input -d 'Generate magnet link from metainfo at `PATH`. If `PATH` is `-`, read metainfo from standard input.'
 complete -c imdl -n "__fish_seen_subcommand_from link" -s p -l peer -d 'Add `PEER` to magnet link.'
-complete -c imdl -n "__fish_seen_subcommand_from link" -s O -l open -d 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows'
+complete -c imdl -n "__fish_seen_subcommand_from link" -s s -l select-only -d 'Select files to download. Values are indices into the `info.files` list, e.g. `--select-only 1,2,3`.'
+complete -c imdl -n "__fish_seen_subcommand_from link" -s O -l open -d 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows.'
 complete -c imdl -n "__fish_seen_subcommand_from link" -s h -l help -d 'Print help message.'
 complete -c imdl -n "__fish_seen_subcommand_from link" -s V -l version -d 'Print version number.'
 complete -c imdl -n "__fish_seen_subcommand_from piece-length" -s h -l help -d 'Print help message.'

completions/imdl.powershell

@@ -132,8 +132,10 @@ Sort in ascending order by size, break ties in descending path order:
             [CompletionResult]::new('--input', 'input', [CompletionResultType]::ParameterName, 'Generate magnet link from metainfo at `PATH`. If `PATH` is `-`, read metainfo from standard input.')
             [CompletionResult]::new('-p', 'p', [CompletionResultType]::ParameterName, 'Add `PEER` to magnet link.')
             [CompletionResult]::new('--peer', 'peer', [CompletionResultType]::ParameterName, 'Add `PEER` to magnet link.')
-            [CompletionResult]::new('-O', 'O', [CompletionResultType]::ParameterName, 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows')
+            [CompletionResult]::new('-s', 's', [CompletionResultType]::ParameterName, 'Select files to download. Values are indices into the `info.files` list, e.g. `--select-only 1,2,3`.')
-            [CompletionResult]::new('--open', 'open', [CompletionResultType]::ParameterName, 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows')
+            [CompletionResult]::new('--select-only', 'select-only', [CompletionResultType]::ParameterName, 'Select files to download. Values are indices into the `info.files` list, e.g. `--select-only 1,2,3`.')
+            [CompletionResult]::new('-O', 'O', [CompletionResultType]::ParameterName, 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows.')
+            [CompletionResult]::new('--open', 'open', [CompletionResultType]::ParameterName, 'Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows.')
             [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Print help message.')
             [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Print help message.')
             [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Print version number.')

completions/imdl.zsh

@@ -135,8 +135,10 @@ _arguments "${_arguments_options[@]}" \
 '--input=[Generate magnet link from metainfo at `PATH`. If `PATH` is `-`, read metainfo from standard input.]' \
 '*-p+[Add `PEER` to magnet link.]' \
 '*--peer=[Add `PEER` to magnet link.]' \
-'-O[Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows]' \
+'*-s+[Select files to download. Values are indices into the `info.files` list, e.g. `--select-only 1,2,3`.]' \
-'--open[Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows]' \
+'*--select-only=[Select files to download. Values are indices into the `info.files` list, e.g. `--select-only 1,2,3`.]' \
+'-O[Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows.]' \
+'--open[Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; `open` on macOS; and `cmd /C start` on Windows.]' \
 '-h[Print help message.]' \
 '--help[Print help message.]' \
 '-V[Print version number.]' \

man/imdl-torrent-link.1

@@ -19,6 +19,10 @@ and `cmd \fI\,/C\/\fP start` on Windows
 Print version number.
 .SH "OPTIONS:"
 .TP
+\fB\-s\fR, \fB\-\-select\-only\fR <INDICES>...
+Specify files that torrent clients select for download. Values are indices into
+the info.files list. e.g. `\-\-select\-only 1,2,3`
+.TP
 \fB\-i\fR, \fB\-\-input\fR <METAINFO>
 Generate magnet link from metainfo at `PATH`. If `PATH` is `\-`, read metainfo from
 standard input.

src/magnet_link.rs

@@ -5,6 +5,7 @@ pub(crate) struct MagnetLink {
   name: Option<String>,
   peers: Vec<HostPort>,
   trackers: Vec<Url>,
+  indices: BTreeSet<u64>,
 }
 
 impl MagnetLink {
@@ -26,6 +27,7 @@ impl MagnetLink {
       name: None,
       peers: Vec::new(),
       trackers: Vec::new(),
+      indices: BTreeSet::new(),
     }
   }
 
@@ -43,6 +45,10 @@ impl MagnetLink {
     self.trackers.push(tracker);
   }
 
+  pub(crate) fn add_index(&mut self, index: u64) {
+    self.indices.insert(index);
+  }
+
   pub(crate) fn to_url(&self) -> Url {
     let mut url = Url::parse("magnet:").unwrap();
 
@@ -63,6 +69,16 @@ impl MagnetLink {
       query.push_str(&peer.to_string());
     }
 
+    if !self.indices.is_empty() {
+      query.push_str("&so=");
+      for (i, selection_index) in self.indices.iter().enumerate() {
+        if i > 0 {
+          query.push(',');
+        }
+        query.push_str(&selection_index.to_string());
+      }
+    }
+
     url.set_query(Some(&query));
 
     url
@@ -129,6 +145,19 @@ mod tests {
     );
   }
 
+  #[test]
+  fn with_indices() {
+    let mut link = MagnetLink::with_infohash(Infohash::from_bencoded_info_dict("".as_bytes()));
+    link.add_index(4);
+    link.add_index(6);
+    link.add_index(6);
+    link.add_index(2);
+    assert_eq!(
+      link.to_url().as_str(),
+      "magnet:?xt=urn:btih:da39a3ee5e6b4b0d3255bfef95601890afd80709&so=2,4,6"
+    );
+  }
+
   #[test]
   fn complex() {
     let mut link = MagnetLink::with_infohash(Infohash::from_bencoded_info_dict("".as_bytes()));

src/subcommand/torrent/link.rs

@@ -21,7 +21,7 @@ pub(crate) struct Link {
     long = "open",
     short = "O",
     help = "Open generated magnet link. Uses `xdg-open`, `gnome-open`, or `kde-open` on Linux; \
-            `open` on macOS; and `cmd /C start` on Windows"
+            `open` on macOS; and `cmd /C start` on Windows."
   )]
   open: bool,
   #[structopt(
@@ -31,6 +31,15 @@ pub(crate) struct Link {
     help = "Add `PEER` to magnet link."
   )]
   peers: Vec<HostPort>,
+  #[structopt(
+    long = "select-only",
+    short = "s",
+    value_name = "INDICES",
+    use_delimiter = true,
+    help = "Select files to download. Values are indices into the `info.files` list, e.g. \
+            `--select-only 1,2,3`."
+  )]
+  indices: Vec<u64>,
 }
 
 impl Link {
@@ -52,6 +61,10 @@ impl Link {
       link.add_peer(peer);
     }
 
+    for index in self.indices {
+      link.add_index(index);
+    }
+
     let url = link.to_url();
 
     outln!(env, "{}", url)?;
@@ -194,6 +207,42 @@ mod tests {
     );
   }
 
+  #[test]
+  fn with_indices() {
+    let mut env = test_env! {
+      args: [
+        "torrent",
+        "link",
+        "--input",
+        "foo.torrent",
+        "--select-only",
+        "2,4",
+        "--select-only",
+        "4,6",
+      ],
+      tree: {
+        "foo.torrent": "d\
+          8:announce24:https://foo.com/announce\
+          4:infod6:lengthi0e4:name3:foo12:piece lengthi1e6:pieces0:e\
+        e",
+      }
+    };
+
+    env.assert_ok();
+
+    const INFO: &str = "d6:lengthi0e4:name3:foo12:piece lengthi1e6:pieces0:e";
+
+    let infohash = Sha1Digest::from_data(INFO.as_bytes());
+
+    assert_eq!(
+      env.out(),
+      format!(
+        "magnet:?xt=urn:btih:{}&dn=foo&tr=https://foo.com/announce&so=2,4,6\n",
+        infohash
+      ),
+    );
+  }
+
   #[test]
   fn infohash_correct_with_nonstandard_info_dict() {
     let mut env = test_env! {