pkgs/den-http-get-updater: init

pkgs/by-name/de/den-http-get-updater/package.nix

@@ -0,0 +1,106 @@
+{
+  lib,
+
+  curl,
+  gawk,
+  jq,
+  nix,
+  writeScript,
+}:
+
+{
+  # location of file to modify
+  fileLocation,
+  previousHash,
+  previousVersion,
+  versionUrl,
+  prefetchUrlLocation ? null,
+  # change newVersion variable in it, if the contents of the page
+  # is not plaintext version
+  # (json for example)
+  contentParser ? "echo \"$newVersion\"",
+
+  unpack ? true,
+  name ? if unpack then "source" else null,
+}:
+
+assert builtins.isNull prefetchUrlLocation || lib.isAttrs prefetchUrlLocation;
+assert lib.isAttrs prefetchUrlLocation && (
+  lib.isString prefetchUrlLocation.file or null ||
+  lib.isPath prefetchUrlLocation.file or null
+);
+assert lib.isAttrs prefetchUrlLocation && lib.isString prefetchUrlLocation.attrpath or null;
+
+let
+  realFileLocation = builtins.toString fileLocation;
+  mark = builtins.hashString "sha256" previousHash;
+
+  mark' = lib.escapeShellArg mark;
+  prefetchUrlLocation' = lib.mapAttrs (_: lib.escapeShellArg) prefetchUrlLocation;
+  realFileLocation' = lib.escapeShellArg realFileLocation;
+  versionUrl' = lib.escapeShellArg versionUrl;
+
+  mark'' = lib.escapeShellArg (lib.escapeRegex mark);
+  previousVersion'' = lib.escapeShellArg (lib.escapeRegex previousVersion);
+
+  nixUnpack = lib.optionalString unpack "--unpack";
+  nixName = lib.optionalString (!builtins.isNull name) "--name \"${lib.escapeShellArg name}\"";
+
+  path = lib.makeBinPath [
+    curl
+    gawk
+    jq
+    nix
+  ];
+in
+
+writeScript "den-http-get-updater" (''
+  PATH="${lib.escapeShellArg path}"
+
+  newVersion=$(curl -L "${versionUrl'}")
+  if [[ "$?" != 0 ]]; then
+    echo "error: fetching new version failed" 1>&2
+    exit 1
+  fi
+  newVersion=$(${contentParser})
+  awk -i inplace "{
+    sub(/${previousVersion''}/, \"$newVersion\")
+    # invalidate hash
+    sub(/${previousHash}/, \"${mark'}\")
+  }1" "${realFileLocation'}"
+'' + lib.optionalString (!builtins.isNull prefetchUrlLocation) ''
+  nixUrlsResult=$(nix-instantiate --eval --json \
+    "${prefetchUrlLocation'.file}" \
+    -A "${prefetchUrlLocation'.attrpath}"
+  )
+
+  urlsType=$(jq -rc 'type' <<< "$nixUrlsResult")
+  if [ "$urlsType" = "array" ]; then
+      readarray -t prefetchUrls < <(
+          jq -rc '.[]' <<< "$nixUrlsResult"
+      )
+  elif [ "$urlsType" = "string" ]; then
+      readarray -t prefetchUrls < <(
+          jq -rc '.' <<< "$nixUrlsResult"
+      )
+  fi
+
+  prefetchSucceeded=1
+  for url in "''${prefetchUrls[@]}"; do
+      echo "trying prefetch '$url'...";
+      expectedHash=$(nix-prefetch-url "$url" ${nixUnpack} ${nixName})
+      if [[ -n $expectedHash ]]; then
+          echo "prefetch succeeded!"
+          echo "hash: $expectedHash"
+          awk -i inplace "{
+            sub(/${mark''}/, \"$expectedHash\")
+          }1" "${realFileLocation'}"
+          prefetchSucceeded=
+          break
+      fi
+  done
+  if [[ -n "$prefetchSucceeded" ]]; then
+      echo "warning: prefetch failed" 1>&2
+      exit 1
+  fi
+'')