19792: Use binary mode in cookbook download+upload examples

This incorporates a suggestion from review to use a binary mode in a way
that makes the recipes more robust. It's very likely that readers will
want to work with binary files at least as much as text files, and these
recipes still work for text files too for verbatim copies.

Refs #19792.

Arvados-DCO-1.1-Signed-off-by: Brett Smith <brett.smith@curii.com>

diff --git a/doc/sdk/python/cookbook.html.textile.liquid b/doc/sdk/python/cookbook.html.textile.liquid
index 43d694d48466ad5b7a5cff75e5127429d8dded48..f2d087625e662347d44f2b458159c97a926dfe2b 100644 (file)
--- a/doc/sdk/python/cookbook.html.textile.liquid
+++ b/doc/sdk/python/cookbook.html.textile.liquid
@@ -396,15 +396,15 @@ with collection.open('ExampleFile') as my_file:
 
 h3(#download-a-file-from-a-collection). Download a file from a collection
 
-Once you have a @Collection@ object, the "@Collection.open@ method":{{ site.baseurl }}/sdk/python/arvados/collection.html#arvados.collection.RichCollectionBase.open lets you open files from a collection the same way you would open files from disk using Python's built-in @open@ function. It returns a file-like object that you can use in many of the same ways you would use any other file object. You can pass it as a source to Python's standard "@shutil.copyfileobj@ function":https://docs.python.org/3/library/shutil.html#shutil.copyfileobj to download it. This code downloads @ExampleFile@ from your collection and saves it to the current working directory as @ExampleDownload@:
+Once you have a @Collection@ object, the "@Collection.open@ method":{{ site.baseurl }}/sdk/python/arvados/collection.html#arvados.collection.RichCollectionBase.open lets you open files from a collection the same way you would open files from disk using Python's built-in @open@ function. You pass a second mode argument like @'rb'@ to open the file in binary mode. It returns a file-like object that you can use in many of the same ways you would use any other file object. You can pass it as a source to Python's standard "@shutil.copyfileobj@ function":https://docs.python.org/3/library/shutil.html#shutil.copyfileobj to download it. This code downloads @ExampleFile@ from your collection and saves it to the current working directory as @ExampleDownload@:
 
 {% codeblock as python %}
 import arvados.collection
 import shutil
 collection = arvados.collection.Collection(...)
 with (
-  collection.open('ExampleFile') as src_file,
-  open('ExampleDownload', 'w') as dst_file,
+  collection.open('ExampleFile', 'rb') as src_file,
+  open('ExampleDownload', 'wb') as dst_file,
 ):
     shutil.copyfileobj(src_file, dst_file)
 {% endcodeblock %}
@@ -432,8 +432,8 @@ import arvados.collection
 import shutil
 collection = arvados.collection.Collection(...)
 with (
-  open('ExampleFile') as src_file,
-  collection.open('ExampleUpload', 'w') as dst_file,
+  open('ExampleFile', 'rb') as src_file,
+  collection.open('ExampleUpload', 'wb') as dst_file,
 ):
     shutil.copyfileobj(src_file, dst_file)
 collection.save_new(...)  # or collection.save() to update an existing collection