如何将 AWS S3 url 转换为 boto 的存储桶名称？

Question

I'm trying to access the http://s3.amazonaws.com/commoncrawl/parse-output/segment/ bucket with boto. I can't figure out how to translate this into a name for boto.s3.bucket.Bucket().

This is the gist of what I'm going for:

s3 = boto.connect_s3()
cc = boto.s3.bucket.Bucket(connection=s3, name='commoncrawl/parse-output/segment')
requester = {'x-amz-request-payer':'requester'}
contents = cc.list(headers=requester)
for i,item in enumerate(contents):
    print item.__repr__()

I get "boto.exception.S3ResponseError: S3ResponseError: 400 Bad Request... The specified bucket is not valid..."

Answer 1

TheAWS documents list four possible url formats for S3 -- here's something I just threw together to extract the bucket and region for all of the different url formats.

import re

def bucket_name_from_url(url):
    """ Gets bucket name and region from url, matching any of the different formats for S3 urls 
    * http://bucket.s3.amazonaws.com
    * http://bucket.s3-aws-region.amazonaws.com
    * http://s3.amazonaws.com/bucket
    * http://s3-aws-region.amazonaws.com/bucket

    returns bucket name, region
    """       
    match =  re.search('^https?://(.+).s3.amazonaws.com/', url)
    if match:
        return match.group(1), None

    match =  re.search('^https?://(.+).s3-([^.]+).amazonaws.com/', url)
    if match:
        return match.group(1), match.group(2)

    match = re.search('^https?://s3.amazonaws.com/([^\/]+)', url)
    if match:
        return match.group(1), None

    match =  re.search('^https?://s3-([^.]+).amazonaws.com/([^\/]+)', url)
    if match:
        return match.group(2), match.group(1)

    return None, None

Something like this should really go into boto... Amazon, I hope you're listening

EDIT 10/10/2018 : The bucket regexes should now capture bucket names with periods.

Answer 2

Extended Marks answer to return keys

#!/usr/bin/env python

import re

def parse_s3_url(url):
    # returns bucket_name, region, key

    bucket_name = None
    region = None
    key = None

    # http://bucket.s3.amazonaws.com/key1/key2
    match = re.search('^https?://([^.]+).s3.amazonaws.com(.*?)$', url)
    if match:
        bucket_name, key = match.group(1), match.group(2)

    # http://bucket.s3-aws-region.amazonaws.com/key1/key2
    match = re.search('^https?://([^.]+).s3-([^\.]+).amazonaws.com(.*?)$', url)
    if match:
        bucket_name, region, key = match.group(1), match.group(2), match.group(3)

    # http://s3.amazonaws.com/bucket/key1/key2
    match = re.search('^https?://s3.amazonaws.com/([^\/]+)(.*?)$', url)
    if match:
        bucket_name, key = match.group(1), match.group(2)

    # http://s3-aws-region.amazonaws.com/bucket/key1/key2
    match = re.search('^https?://s3-([^.]+).amazonaws.com/([^\/]+)(.*?)$', url)
    if match:
        bucket_name, region, key = match.group(2), match.group(1), match.group(3)

    return list( map(lambda x: x.strip('/') if x else None, [bucket_name, region, key] ) )

Answer 3

The bucket name would be commoncrawl. Everything that appears after that is really just part of the name of the keys that appear in the bucket.

Answer 4

Here it is my JS version:

function parseS3Url(url) {
  // Process all aws s3 url cases

  url = decodeURIComponent(url);
  let match = "";

  // http://s3.amazonaws.com/bucket/key1/key2
  match = url.match(/^https?:\/\/s3.amazonaws.com\/([^\/]+)\/?(.*?)$/);
  if (match) {
    return {
      bucket: match[1],
      key: match[2],
      region: ""
    };
  }

  // http://s3-aws-region.amazonaws.com/bucket/key1/key2
  match = url.match(/^https?:\/\/s3-([^.]+).amazonaws.com\/([^\/]+)\/?(.*?)$/);
  if (match) {
    return {
      bucket: match[2],
      key: match[3],
      region: match[1]
    };
  }

  // http://bucket.s3.amazonaws.com/key1/key2
  match = url.match(/^https?:\/\/([^.]+).s3.amazonaws.com\/?(.*?)$/);
  if (match) {
    return {
      bucket: match[1],
      key: match[2],
      region: ""
    };
  }

  // http://bucket.s3-aws-region.amazonaws.com/key1/key2
  match = url.match(/^https?:\/\/([^.]+).s3-([^\.]+).amazonaws.com\/?(.*?)$/);
  if (match) {
    return {
      bucket: match[1],
      key: match[3],
      region: match[2]
    };
  }

  return {
    bucket: "",
    key: "",
    region: ""
  };
}

Answer 5

Basing on Mark's answer I've made a small pyparsing script that is clearer to me (include possible key matches):

#!/usr/bin/env python

from pyparsing import Word, alphanums, Or, Optional, Combine

schema = Or(['http://', 'https://']).setResultsName('schema')
word = Word(alphanums + '-', min=1)
bucket_name = word.setResultsName('bucket')
region = word.setResultsName('region')

key = Optional('/' + word.setResultsName('key'))

"bucket.s3.amazonaws.com"
opt1 = Combine(schema + bucket_name + '.s3.amazonaws.com' + key)

"bucket.s3-aws-region.amazonaws.com"
opt2 = Combine(schema + bucket_name + '.' + region + '.amazonaws.com' + key)

"s3.amazonaws.com/bucket"
opt3 = Combine(schema + 's3.amazonaws.com/' + bucket_name + key)

"s3-aws-region.amazonaws.com/bucket"
opt4 = Combine(schema + region + ".amazonaws.com/" + bucket_name + key)

tests = [
    "http://bucket-name.s3.amazonaws.com",
    "https://bucket-name.s3-aws-region-name.amazonaws.com",
    "http://s3.amazonaws.com/bucket-name",
    "https://s3-aws-region-name.amazonaws.com/bucket-name",
    "http://bucket-name.s3.amazonaws.com/key-name",
    "https://bucket-name.s3-aws-region-name.amazonaws.com/key-name",
    "http://s3.amazonaws.com/bucket-name/key-name",
    "https://s3-aws-region-name.amazonaws.com/bucket-name/key-name",
]

s3_url = Or([opt1, opt2, opt3, opt4]).setResultsName('url')

for test in tests:
    result = s3_url.parseString(test)
    print "found url: " + str(result.url)
    print "schema: " + str(result.schema)
    print "bucket name: " + str(result.bucket)
    print "key name: " + str(result.key)

Originally I made Mark's script also retrieve the key (object):

def parse_s3_url(url):
    """ Gets bucket name and region from url, matching any of the different formats for S3 urls
    * http://bucket.s3.amazonaws.com
    * http://bucket.s3-aws-region.amazonaws.com
    * http://s3.amazonaws.com/bucket
    * http://s3-aws-region.amazonaws.com/bucket

    returns bucket name, region
    """
    match = re.search('^https?://([^.]+).s3.amazonaws.com(/\([^.]+\))', url)
    if match:
        return match.group(1), None, match.group(2)

    match = re.search('^https?://([^.]+).s3-([^.]+).amazonaws.com/', url)
    if match:
        return match.group(1), match.group(2), match.group(3)

    match = re.search('^https?://s3.amazonaws.com/([^\/]+)', url)
    if match:
        return match.group(1), None, match.group(2)

    match = re.search('^https?://s3-([^.]+).amazonaws.com/([^\/]+)', url)
    if match:
        return match.group(2), match.group(1), match.group(3)

    return None, None, None

Answer 6

The other answers would not support S3 urls like "s3://bucket/key", so I wrote a python function inspired on the Java wrapper :

def bucket_name_from_url(url):
"""
A URI wrapper that can parse out information about an S3 URI.
Implementation based on com.amazonaws.services.s3.AmazonS3URI
:param url: the URL to parse
:return: the bucket and the key
"""
uri = urlparse(url)

if uri.scheme == "s3":
    bucket = uri.netloc
    path = uri.path
    if len(path) <= 1:
        # s3://bucket or s3://bucket/
        key = None
    else:
        # s3://bucket/key
        # Remove the leading '/'.
        key = path[1:]

    return bucket, key

match = re.search('^https://(.+\.)?s3[.-]([a-z0-9-]+)\.', url)
prefix = match.group(1)

if not prefix:
    # No bucket name in the authority; parse it from the path.
    path = uri.path
    index = path.find('/', 1)
    if index == -1:
        # https://s3.amazonaws.com/bucket
        bucket = urllib.unquote(path[1:])
        key = None
    elif index == (len(path) - 1):
        # https://s3.amazonaws.com/bucket/
        bucket = urllib.unquote(path[1:index])
        key = None
    else:
        bucket = urllib.unquote(path[1:index])
        key = urllib.unquote(path[index+1:])
else:
    # Bucket name was found in the host; path is the key.
    bucket = prefix[0:len(prefix)-1]
    path = uri.path
    if not path or path == "/":
        key = None
    else:
        # Remove the leading '/'.
        key = path[1:]

return bucket, key