Initial commit with initial data URI conversion implementation.

src/data_uri.nim

@@ -0,0 +1,88 @@
+## Data URI Utilities
+
+import base64, docopt, filetype, logging, nre, os
+from strutils import isEmptyOrWhitespace
+
+include "data_uripkg/version.nim"
+
+let dataUriPattern = re"^data:([^;,]+)?(;base64)?,(.+)$"
+
+
+proc encodeAsDataUri*(value: string, mimeType: string = ""): string =
+  let actualMimeType =
+    if mimeType.isEmptyOrWhitespace: filetype.match(cast[seq[byte]](value)).mime.value
+    else: mimeType
+
+  let encoded = encode(value)
+
+  return "data:" & actualMimeType & ";base64," & encoded
+
+
+proc decodeDataUri*(dataUri: string): string =
+  let parseMatch = dataUri.match(dataUriPattern)
+
+  if not parseMatch.isSome:
+    raise newException(Exception, "input does not look like a valid data URI")
+
+  let encodedData = parseMatch.get.captures[2]
+  return decode(encodedData)
+
+when isMainModule:
+
+  try:
+    let doc = """
+Usage:
+  data_uri encode [options]
+  data_uri decode [options]
+
+Options:
+
+  -h, --help              Print this usage information.
+
+  -i, --input <inFile>    Read input from inFile rather than from stdin (the
+                          default).
+
+  -o, --output <outFile>  Write output to outFile rather than to stdout (the
+                          default).
+
+  -t, --type <mimeType>   Manually set the MIME type rather than trying to
+                          infer it from the file extension. This only applies
+                          when encoding files to data-uris.
+"""
+
+    logging.addHandler(newConsoleLogger())
+
+    # Parse arguments
+    let args = docopt(doc, version = DATA_URI_VERSION)
+
+    if args["--help"]:
+      stderr.writeLine(doc)
+      quit()
+
+    if args["--input"] and not fileExists($args["--input"]):
+      raise newException(Exception, "'" & $args["--input"] & "' is not a valid file.'")
+
+    let fileIn =
+      if args["--input"]: open($args["--input"])
+      else: stdin
+
+    let fileOut =
+      if args["--output"]: open($args["--output"], fmWrite)
+      else: stdout
+
+    try:
+      if args["encode"]:
+        let binaryData = readAll(fileIn)
+        write(fileOut, encodeAsDataUri(binaryData))
+
+      if args["decode"]:
+        let dataUri = readAll(fileIn)
+        write(fileOut, decodeDataUri(dataUri))
+
+    finally:
+      close(fileIn)
+      close(fileOut)
+
+  except:
+    fatal "data_uri: " & getCurrentExceptionMsg()
+    quit(QuitFailure)

src/data_uripkg/version.nim

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+const DATA_URI_VERSION* = "0.1.0"