adds API for streaming torrents

codex/bittorrent/manifest/manifest.nim

@@ -15,6 +15,7 @@ type
     name*: ?string
 
   BitTorrentInfoHash* = MultiHash
+  BitTorrentInfoHashV1* = distinct array[20, byte]
 
   BitTorrentManifest* = ref object
     info*: BitTorrentInfo
@@ -25,6 +26,11 @@ proc newBitTorrentManifest*(
 ): BitTorrentManifest =
   BitTorrentManifest(info: info, codexManifestCid: codexManifestCid)
 
+# needed to be able to create a MultiHash from BitTorrentInfoHashV1
+proc init*(
+  mhtype: typedesc[MultiHash], hashname: string, bdigest: BitTorrentInfoHashV1
+): MhResult[MultiHash] {.borrow.}
+
 func bencode*(info: BitTorrentInfo): seq[byte] =
   # flatten pieces
   var pieces: seq[byte]

codex/rest/api.nim

@@ -39,6 +39,7 @@ import ../manifest
 import ../streams/asyncstreamwrapper
 import ../stores
 import ../utils/options
+import ../bittorrent/manifest
 
 import ./coders
 import ./json
@@ -181,7 +182,7 @@ proc getFilenameFromContentDisposition(contentDisposition: string): ?string =
   return filename[0 ..^ 2].some
 
 proc initDataApi(node: CodexNodeRef, repoStore: RepoStore, router: var RestRouter) =
-  let allowedOrigin = router.allowedOrigin # prevents capture inside of api defintion
+  let allowedOrigin = router.allowedOrigin # prevents capture inside of api definition
 
   router.api(MethodOptions, "/api/codex/v1/data") do(
     resp: HttpResponseRef
@@ -347,6 +348,25 @@ proc initDataApi(node: CodexNodeRef, repoStore: RepoStore, router: var RestRoute
     resp.setHeader("Access-Control-Expose-Headers", "Content-Disposition")
     await node.retrieveCid(cid.get(), local = false, resp = resp)
 
+  router.api(MethodGet, "/api/codex/v1/data/{infoHash}/network/torrent") do(
+    infoHash: BitTorrentInfoHashV1, resp: HttpResponseRef
+  ) -> RestApiResponse:
+    var headers = buildCorsHeaders("GET", allowedOrigin)
+
+    without infoHash =? infoHash.tryGet.catch, error:
+      return RestApiResponse.error(Http400, error.msg, headers = headers)
+
+    without infoMultiHash =? MultiHash.init($Sha1HashCodec, infoHash).mapFailure, error:
+      return RestApiResponse.error(Http400, error.msg, headers = headers)
+
+    if corsOrigin =? allowedOrigin:
+      resp.setCorsHeaders("GET", corsOrigin)
+      resp.setHeader("Access-Control-Headers", "X-Requested-With")
+
+    trace "torrent requested: ", multihash = $infoMultiHash
+
+    return RestApiResponse.response(Http200)
+
   router.api(MethodGet, "/api/codex/v1/data/{cid}/network/manifest") do(
     cid: Cid, resp: HttpResponseRef
   ) -> RestApiResponse:

codex/rest/coders.nim

@@ -21,6 +21,8 @@ import ../sales
 import ../purchasing
 import ../utils/stintutils
 
+from ../bittorrent/manifest import BitTorrentInfoHashV1
+
 proc encodeString*(cid: type Cid): Result[string, cstring] =
   ok($cid)
 
@@ -82,6 +84,19 @@ proc decodeString*(
   except ValueError as e:
     err e.msg.cstring
 
+proc decodeString*(
+    _: type array[20, byte], value: string
+): Result[array[20, byte], cstring] =
+  try:
+    ok array[20, byte].fromHex(value)
+  except ValueError as e:
+    err e.msg.cstring
+
+proc decodeString*[T: BitTorrentInfoHashV1](
+    _: type T, value: string
+): Result[T, cstring] =
+  array[20, byte].decodeString(value).map(id => T(id))
+
 proc decodeString*[T: PurchaseId | RequestId | Nonce | SlotId | AvailabilityId](
     _: type T, value: string
 ): Result[T, cstring] =