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Rackspace Cloud Files Erlang Client

Description

This is an Erlang interface into the Rackspace Cloud Files service. It has been largely inspired by the existing Ruby API.

Building

cferl relies on rebar for its build and dependency management and targets Erlang/OTP R13B04 or above.

Simply run:

rebar get-deps compile eunit

Optionally, to generate the cferl documentation, run:

rebar skip_deps=true doc

Optionally, to run the integration tests (and generate the code samples visible below), run:

./int_tests

If you run the integration tests, you'll need your API key and at least one pre-existing container. Note that a test container will be created and some queries could take a while if you have lots of containers.

Using

cferl requires that the ssl and ibrowse applications be started prior to using it.

The following, which is output when running the integration tests, demonstrates a typical usage of the API. Refer to the documentation for the complete reference.

# Connect to Cloud Files (warning: cache/use CloudFiles for a maximum of 24 hours!)
{ok,CloudFiles}=cferl:connect(Username,ApiKey).

# Retrieve the account information record
{ok,Info}=cferl_connection:get_account_info(CloudFiles).
Info = #cf_account_info{bytes_used=1735871382, container_count=5}

# Retrieve names of all existing containers (within the limits imposed by Cloud Files server)
{ok,Names}=cferl_connection:get_containers_names(CloudFiles).

# Retrieve names of a maximum of 3 existing containers
{ok,ThreeNamesMax}=cferl_connection:get_containers_names(CloudFiles,#cf_container_query_args{limit=3}).

# Retrieve names of all containers currently CDN activated
{ok,CurrentPublicNames}=cferl_connection:get_public_containers_names(CloudFiles,active).

# Retrieve names of all containers that are currently or have been CDN activated
{ok,AllTimePublicNames}=cferl_connection:get_public_containers_names(CloudFiles,all_time).

# Retrieve details for all existing containers (within the server limits)
{ok,ContainersDetails}=cferl_connection:get_containers_details(CloudFiles).

# ContainersDetails is a list of #cf_container_details records
[ContainerDetails|_]=ContainersDetails.
ContainerDetails = #cf_container_details{name=<<".CDN_ACCESS_LOGS">>, bytes=261, count=1}

# Retrieve details for a maximum of 5 containers whose names start at cf
{ok,CfContainersDetails}=cferl_connection:get_containers_details(CloudFiles,#cf_container_query_args{marker=<<"cf">>,limit=5}).

# Get a container reference by name
{ok,Container}=cferl_connection:get_container(CloudFiles,ContainerDetails#cf_container_details.name).

# Get container details from its reference
ContainerName=cferl_container:name(Container).
ContainerBytes=cferl_container:bytes(Container).
ContainerSize=cferl_container:count(Container).
ContainerIsEmpty=cferl_container:is_empty(Container).

# -> Name: <<".CDN_ACCESS_LOGS">> - Bytes: 261 - Size: 1 - IsEmpty: false

# Check a container's existence
false=cferl_connection:container_exists(CloudFiles,NewContainerName).

# Create a new container
{ok,NewContainer}=cferl_connection:create_container(CloudFiles,NewContainerName).

true=cferl_connection:container_exists(CloudFiles,NewContainerName).

Check attributes of this newly created container
NewContainerName=cferl_container:name(NewContainer).
0=cferl_container:bytes(NewContainer).
0=cferl_container:count(NewContainer).
true=cferl_container:is_empty(NewContainer).
false=cferl_container:is_public(NewContainer).
<<>>=cferl_container:cdn_url(NewContainer).
0=cferl_container:cdn_ttl(NewContainer).
false=cferl_container:log_retention(NewContainer).

# Make the container public on the CDN (using the default TTL and ACLs)
ok=cferl_container:make_public(CloudFiles,NewContainer).

# Activate log retention on the new container
ok=cferl_container:set_log_retention(CloudFiles,NewContainer,true).

# Refresh an existing container and check its attributes
{ok,RefreshedContainer}=cferl_container:refresh(CloudFiles,NewContainer).
true=cferl_container:is_public(RefreshedContainer).

io:format("~s~n~n",[cferl_container:cdn_url(RefreshedContainer)]).
http://05f98f987aa9393ccd8c-3d04f8822c5760cb271501bb0c358085.r17.cf1.rackcdn.com

86400=cferl_container:cdn_ttl(RefreshedContainer).
true=cferl_container:log_retention(RefreshedContainer).

ObjectName=<<"test.xml">>.
# Create an object *reference*, nothing is sent to the server yet
{ok,Object}=cferl_container:create_object(CloudFiles,RefreshedContainer,ObjectName).
# As expected, it doesn't exist yet
false=cferl_container:object_exists(CloudFiles,RefreshedContainer,ObjectName).

# Write data in the object, which creates it on the server
ok=cferl_object:write_data(CloudFiles,Object,<<"<test/>">>,<<"application/xml">>).
# Now it exists!
true=cferl_container:object_exists(CloudFiles,RefreshedContainer,ObjectName).
# And trying to re-create it just returns it
{ok,ExistingObject}=cferl_container:create_object(CloudFiles,RefreshedContainer,ObjectName).

# Set custom meta-data on it
ok=cferl_object:set_metadata(CloudFiles,Object,[{<<"Key123">>,<<"my123Value">>}]).

# An existing object can be accessed directly from its container
{ok,GotObject}=cferl_container:get_object(CloudFiles,RefreshedContainer,ObjectName).

# Object names and details can be queried
{ok,[ObjectName]}=cferl_container:get_objects_names(CloudFiles,RefreshedContainer).
{ok,[ObjectName]}=cferl_container:get_objects_names(CloudFiles,RefreshedContainer,#cf_object_query_args{limit=1}).
{ok,[ObjectDetails]}=cferl_container:get_objects_details(CloudFiles,RefreshedContainer).
ObjectDetails = #cf_object_details{name=<<"test.xml">>, bytes=8, last_modified={{2013,3,16},{0,8,47}}, content_type=application/xml, etag=4366c359d1a7b9b248fa262775613699}

# Read the whole data
{ok,<<"<test/>">>}=cferl_object:read_data(CloudFiles,Object).
# Read the data with an offset and a size
{ok,<<"test">>}=cferl_object:read_data(CloudFiles,Object,1,4).

# Refresh the object so its attributes and metadata are up to date
{ok,RefreshedObject}=cferl_object:refresh(CloudFiles,Object).

# Get object attributes
ObjectName=cferl_object:name(RefreshedObject).
8=cferl_object:bytes(RefreshedObject).
{{D,M,Y},{H,Mi,S}}=cferl_object:last_modified(RefreshedObject).
<<"application/xml">>=cferl_object:content_type(RefreshedObject).
Etag=cferl_object:etag(RefreshedObject).

# Get custom meta-data
[{<<"Key123">>,<<"my123Value">>}]=cferl_object:metadata(RefreshedObject).

# Delete the object
ok=cferl_object:delete(CloudFiles,RefreshedObject).

# Data can be streamed to the server from a generating function
{ok,StreamedObject}=cferl_container:create_object(CloudFiles,RefreshedContainer,<<"streamed.txt">>).
cferl_object:write_data_stream(CloudFiles,StreamedObject,WriteDataFun,<<"text/plain">>,1000).

# Data can be streamed from the server to a receiving function
ok=cferl_object:read_data_stream(CloudFiles,StreamedObject,ReadDataFun).

# Create all the directory elements for a particular object path
ok=cferl_container:ensure_dir(CloudFiles,RefreshedContainer,<<"photos/plants/fern.jpg">>).
true=cferl_container:object_exists(CloudFiles,RefreshedContainer,<<"photos">>).
true=cferl_container:object_exists(CloudFiles,RefreshedContainer,<<"photos/plants">>).

# Make the container private
ok=cferl_container:make_private(CloudFiles,RefreshedContainer).

# Delete an existing container (must be empty)
ok=cferl_container:delete(CloudFiles,RefreshedContainer).

More information

Read the Rackspace Cloud Files API specification: http://www.rackspacecloud.com/cloud_hosting_products/files/api