CODEWITHSUNDEEP
pythonsyntax
sirvon
sirvon

Reputation: 2615

var inside of brackets

I have this ....

   fileExt = {'png': "'Content-Type': 'image/png'", 'jpe': "'Content-Type':
   'image/jpeg'", 'jpg': "'Content-Type': 'image/jpeg'", 
   'png': "Content-Type': 'image/png'", 'mp4': "'Content-Type': 'video/mpeg'",
   'mp3': "'Content-Type': 'audio/mpeg'", '3gp': "'Content-Type': 'video/3gpp'",
   'flv': "'Content-Type': 'video/x-flv'", 'flv': "'Content-Type': 'video/x-flv'"}
   handler = fileExt.get(ext)
   go = "'"+handler
   key.copy(key.bucket, key.name, preserve_acl=True, metadata={go})

i'm getting this error...

   Traceback (most recent call last):
  File "s3ContentType.py", line 43, in <module>
   key.copy(key.bucket, key.name, preserve_acl=True, metadata={go})
  File "/task/__pips__/boto/s3/key.py", line 474, in copy
   encrypt_key=encrypt_key)
  File "/task/__pips__/boto/s3/bucket.py", line 723, in copy_key
   headers = boto.utils.merge_meta(headers, metadata, provider)
  File "/task/__pips__/boto/utils.py", line 172, in merge_meta
   for k in metadata.keys():
AttributeError: 'set' object has no attribute 'keys'

But if i explicitly put a string inside the metadata brackets it works.

  key.copy(key.bucket, key.name, preserve_acl=True, metadata={'Content-Type': 'image/png'})

What gives, how do i include a var inside the brackets

Upvotes: 2

Views: 484

Answers (3)

Jonas Sch&#228;fer
Jonas Sch&#228;fer

Reputation: 20718

You are constructing two different objects here:

foo = {'a', 'b', 'c'}

is a set, while

bar = {'a': 'b', 'c': 'd'}

is a dictionary. You can of course reference variables when constructing a dict:

mimetype = "image/png"
bar = {'Content-Type': mimetype}

A dictionary maps keys to values (hence the :), while the set is only a collection of distinct values. The funciton you're calling expects a dictionary, so you have to create one. If you have a dictionary and want to pass that (continuing from above), you can do that like this:

mimetype = "image/png"
bar = {'Content-Type': mimetype}
key.copy(key.bucket, key.name, preserve_acl=True, metadata=bar)

(note that the links go to python 3 documentation, but sets and dicts have not really changed since python 2)

For the edit: As the accepted answer said, you have to use a nested dictionary. The question is, why doesn't it work otherwise?

Otherwise, you're creating a set containing the string you previously stored in the fileExt dictionary, for example "Content-Type: 'image/png'". Python will not interpret this string, which is why it does not create a dictionary when you write {"Content-Type: 'image/png'"}.

Upvotes: 2

its me
its me

Reputation: 127

You can use a nested dictionary as well for keeping file extensions and content like this

    fileExt = {'png': {'Content-Type': 'image/png'}, 'jpe': {'Content-Type':'image/jpeg'}, 
    'jpg': {'Content-Type': 'image/jpeg'}, 'png': {'Content-Type': 'image/png'}, 
    'mp4': {'Content-Type': 'video/mpeg'}, 'mp3': {'Content-Type': 'audio/mpeg'}, 
    '3gp': {'Content-Type': 'video/3gpp'}, 'flv': {'Content-Type': 'video/x-flv'}, 
    'flv': {'Content-Type': 'video/x-flv'}}
    handler = fileExt.get(ext)

then you will be directly using handler in metadata, like this

    key.copy(key.bucket, key.name, preserve_acl=True, metadata=handler)

Upvotes: 1

thefourtheye
thefourtheye

Reputation: 239453

When you say {go} you are actually creating a set, not a dict. And sets don't have keys.

print type({"Welcome"})
print type({"1":"Welcome"})

Output

<type 'set'>
<type 'dict'>

But when you say {'Content-Type': 'image/png'}, you are actually creating a dict and thats why it works.

Upvotes: 1

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