Amazon S3: What are considered PUT/COPY/POST/LIST request?

From my experience using S3 (and also from the basics of HTTP protocol and REST), POST is the creation of a new object (in S3, it would be the upload of a new file), and PUT is a creation of a new object or update of an existing object (i.e., creation or update of a file). Additionally, from S3 docs:

POST is an alternate form of PUT that enables browser-based uploads as a way of putting objects in buckets

Every time you, for example, get the contents of a given S3 bucket, you're running into a LIST operation. You have not asked, but a GET is the download of a file from S3 and DELETE would obviously be the deletion of a file. Of course these assumptions depend on which SDK you are using (it seems you're using the PHP one) and its underlying implementation. My argument is that it is possible to implement a download using a GET, an upload using a PUT or a POST, and so forth.

Taking a look into S3 REST API, though, I assume get_bucket_filesize() is implemented as a LIST (a GET operation on a bucket brings, along with some more data, the size of each object in the response) and get_object_filesize() is implemented as a GET (using the HEAD operation on a single file also brings its size included in the metadata).

Yes, you are right. PUT is uploading (specifically one file is one PUT). I was watching for whether PUT was per file or per some packet size which would make it more difficult to price. It is putting a file (without reference to size).

ALSO, COPY indeed is copying files within S3, but there’s more. See below. I also found references to POST and LIST; see below.

So what I learned about PUT/COPY/POST/LIST and GET Requests while digging in to assess our costs. I’m also including WHERE I discovered it (wanted to get it all from Amazon). All corrections are welcome.

Amazon's FAQ is here: https://aws.amazon.com/s3/faqs/ and I'll reference this below.

COPY can be several things, one of which is copying between regions which does cost. For example, if you store in West VA, and COPY to the Northern CA region, that incurs cost. Copying from EC2 to S3 (within the same region I presume) incurs no transfer cost. See Amazon's FAQ in the section Q: How much does Amazon S3 cost?

NOTE: Writing a file, then re-writing that same file stores both versions (unless you delete something). I’m guessing you are not charged more if the files are exactly the same, but don’t send me the bill if I’m wrong. :-) It seems that the average size (for a month) is what is billed. See FAQ (link above)

For PUT, GET and DELETE, it appears one file is one transaction. That answers a big question for me (I didn’t want their 128k minimum size to be a PUT for each 128k packet… yeah, I’m paranoid). See the Question section like this:

Q: How will I be charged and billed for my use of Amazon S3?

Request Example:

Assume you transfer 10,000 files into Amazon S3 and transfer 20,000 files out of Amazon S3 each day during the month of March. Then, you delete 5,000 files on March 31st.

Total PUT requests = 10,000 requests x 31 days = 310,000 requests

Total GET requests = 20,000 requests x 31 days = 620,000 requests

Total DELETE requests = 5,000×1 day = 5,000 requests

LIST is mentioned under the question: Q: Can I use the Amazon S3 APIs or Management Console to list objects that I’ve archived to Amazon Glacier? It is essentially getting a list of files… a directory, if you will.

POST is mentioned under RESTObjectPost.html here: http://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectPOST.html

I hope that helps. It sure made me more comfortable with what we would be charged.