Merge pull request #1759 from althonos/progress-reader

Add API to support tracking progress while reading from a file

CHANGELOG.md

@@ -5,7 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## 12.1.0
+
+### Added
+
+- Progress.open and Progress.wrap_file method to track the progress while reading from a file or file-like object https://github.com/willmcgugan/rich/pull/1759
 
 ### Added
 

CONTRIBUTORS.md

@@ -18,6 +18,7 @@ The following people have contributed to the development of Rich:
 - [Finn Hughes](https://github.com/finnhughes)
 - [Josh Karpel](https://github.com/JoshKarpel)
 - [Andrew Kettmann](https://github.com/akettmann)
+- [Martin Larralde](https://github.com/althonos)
 - [Hedy Li](https://github.com/hedythedev)
 - [Luka Mamukashvili](https://github.com/UltraStudioLTD)
 - [Alexander Mancevice](https://github.com/amancevice)

docs/source/progress.rst

@@ -26,6 +26,16 @@ For basic usage call the :func:`~rich.progress.track` function, which accepts a
     for n in track(range(n), description="Processing..."):
         do_work(n)
 
+
+To get a progress bar while reading from a file, you may consider using the :func:`~rich.progress.read` function, which accepts a path, or a *file-like* object. It will return a *file-like* object in *binary mode* that will update the progress information as it's being read from. Here's an example, tracking the progresses made by :func:`json.load` to load a file::
+
+    import json
+    from rich.progress import read
+
+    with read("data.json", description="Loading data...") as f:
+        data = json.load(f)
+
+
 Advanced usage
 --------------
 
@@ -34,9 +44,9 @@ If you require multiple tasks in the display, or wish to configure the columns i
 The Progress class is designed to be used as a *context manager* which will start and stop the progress display automatically.
 
 Here's a simple example::
-    
+
     import time
-    
+
     from rich.progress import Progress
 
     with Progress() as progress:
@@ -179,7 +189,7 @@ If you have another Console object you want to use, pass it in to the :class:`~r
     with Progress(console=my_console) as progress:
         my_console.print("[bold blue]Starting work!")
         do_work(progress)
-        
+
 
 Redirecting stdout / stderr
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -199,6 +209,42 @@ If the :class:`~rich.progress.Progress` class doesn't offer exactly what you nee
         def get_renderables(self):
             yield Panel(self.make_tasks_table(self.tasks))
 
+Reading from a file
+~~~~~~~~~~~~~~~~~~~
+
+You can obtain a progress-tracking reader using the :meth:`~rich.progress.Progress.open` method by giving it a path. You can specify the number of bytes to be read, but by default :meth:`~rich.progress.Progress.open` will query the size of the file with :func:`os.stat`. You are responsible for closing the file, and you should consider using a *context* to make sure it is closed ::
+
+    import json
+    from rich.progress import Progress
+
+    with Progress() as progress:
+        with progress.open("data.json", "rb") as file:
+            json.load(file)
+
+
+Note that in the above snippet we use the `"rb"` mode, because we needed the file to be opened in binary mode to pass it to :func:`json.load`. If the API consuming the file is expecting an object in *text mode* (for instance, :func:`csv.reader`), you can open the file with the `"r"` mode, which happens to be the default ::
+
+    from rich.progress import Progress
+
+    with Progress() as progress:
+        with progress.open("README.md") as file:
+            for line in file:
+                print(line)
+
+
+Reading from a file-like object
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+You can obtain a progress-tracking reader wrapping a file-like object using the :meth:`~rich.progress.Progress.wrap_file` method. The file-like object must be in *binary mode*, and a total must be provided, unless it was provided to a :class:`~rich.progress.Task` created beforehand. The returned reader may be used in a context, but will not take care of closing the wrapped file ::
+
+    import json
+    from rich.progress import Progress
+
+    with Progress() as progress:
+        with open("data.json", "rb") as file:
+            json.load(progress.wrap_file(file, total=2048))
+
+
 Multiple Progress
 -----------------
 
@@ -208,4 +254,3 @@ Example
 -------
 
 See `downloader.py <https://github.com/willmcgugan/rich/blob/master/examples/downloader.py>`_ for a realistic application of a progress display. This script can download multiple concurrent files with a progress bar, transfer speed and file size.
-

examples/cp_progress.py

@@ -0,0 +1,39 @@
+"""
+A very minimal `cp` clone that displays a progress bar.
+"""
+import os
+import shutil
+import sys
+
+from rich.progress import (
+    BarColumn,
+    DownloadColumn,
+    Progress,
+    TaskID,
+    TextColumn,
+    TimeRemainingColumn,
+    TransferSpeedColumn,
+)
+
+progress = Progress(
+    TextColumn("[bold blue]{task.description}", justify="right"),
+    BarColumn(bar_width=None),
+    "[progress.percentage]{task.percentage:>3.1f}%",
+    "•",
+    DownloadColumn(),
+    "•",
+    TransferSpeedColumn(),
+    "•",
+    TimeRemainingColumn(),
+)
+
+if __name__ == "__main__":
+    if len(sys.argv) == 3:
+
+        with progress:
+            desc = os.path.basename(sys.argv[1])
+            with progress.read(sys.argv[1], description=desc) as src:
+                with open(sys.argv[2], "wb") as dst:
+                    shutil.copyfileobj(src, dst)
+    else:
+        print("Usage:\n\tpython cp_progress.py SRC DST")