def service_wrapper(func):
@functools.wraps(func)
def wrapper(environ, start_response):
_handle_notify_before(environ, FROM_ENVIRON, notify_before)
# 'service' passes the WSGI request straight through
# to the handler so there's almost no point in
# setting up the environment. However, I can conceive
# of tools which might access 'environ' directly, and
# I want to be consistent with the simple* interfaces.
new_request(environ)
result = func(environ, start_response)
# You need to make sure you sent the correct content-type!
result, ctype, length = convert_body(result, None, encoding, writer)
result = _handle_notify_after(environ, result, notify_after)
return result
pth = path
if pth is None:
pth = func.__name__
# If an outer WSGI wrapper was specified, place it around the service wrapper being created
if wsgi_wrapper:
wrapper = wsgi_wrapper(wrapper)
#For purposes of inspection (not a good idea to change these otherwise you'll lose sync with the values closed over)
wrapper.content_type = content_type
wrapper.encoding = encoding
wrapper.writer = writer
registry.register_service(service_id, pth, wrapper, query_template=query_template)
return wrapper
def register_pipeline(ident, path=None, stages=None, doc=None):
if not stages:
raise TypeError("a pipeline must have stages")
stages = [_normalize_stage(stage) for stage in stages]
# Should I check that the dependent stages are already registered?
pipeline = Pipeline(ident, path, stages, doc)
registry.register_service(ident, path, pipeline, doc)
def method_dispatcher_wrapper(func):
# Have to handle a missing docstring here as otherwise
# the registry will try to get it from the dispatcher.
doc = inspect.getdoc(func) or ""
pth = path
if pth is None:
pth = func.__name__
dispatcher = service_method_dispatcher(pth, wsgi_wrapper)
registry.register_service(service_id, pth, dispatcher, doc)
return service_dispatcher_decorator(dispatcher)
def method_dispatcher_wrapper(func):
# Have to handle a missing docstring here as otherwise
# the registry will try to get it from the dispatcher.
doc = inspect.getdoc(func) or ""
pth = path
if pth is None:
pth = func.__name__
dispatcher = service_method_dispatcher(pth, wsgi_wrapper)
registry.register_service(service_id, pth, dispatcher, doc)
return service_dispatcher_decorator(dispatcher)
def service_wrapper(func):
@functools.wraps(func)
def wrapper(environ, start_response):
_handle_notify_before(environ, FROM_ENVIRON, notify_before)
# 'service' passes the WSGI request straight through
# to the handler so there's almost no point in
# setting up the environment. However, I can conceive
# of tools which might access 'environ' directly, and
# I want to be consistent with the simple* interfaces.
new_request(environ)
result = func(environ, start_response)
# You need to make sure you sent the correct content-type!
result, ctype, length = convert_body(result, None, encoding,
writer)
result = _handle_notify_after(environ, result, notify_after)
return result
pth = path
if pth is None:
pth = func.__name__
# If an outer WSGI wrapper was specified, place it around the service wrapper being created
if wsgi_wrapper:
wrapper = wsgi_wrapper(wrapper)
#For purposes of inspection (not a good idea to change these otherwise you'll lose sync with the values closed over)
wrapper.content_type = content_type
wrapper.encoding = encoding
wrapper.writer = writer
registry.register_service(service_id,
pth,
wrapper,
query_template=query_template)
return wrapper
# This is a very simple implementation of conditional GET with
# the Last-Modified header. It makes media files a bit speedier
# because the files are only read off disk for the first request
# (assuming the browser/client supports conditional GET).
mtime = formatdate(os.stat(filename).st_mtime, usegmt=True)
headers = [('Last-Modified', mtime)]
if environ.get('HTTP_IF_MODIFIED_SINCE', None) == mtime:
status = '304 Not Modified'
output = ()
else:
status = '200 OK'
mime_type = mimetypes.guess_type(filename)[0]
if mime_type:
headers.append(('Content-Type', mime_type))
output = [fp.read()]
fp.close()
start_response(status, headers)
return output
import akara
if not akara.module_config():
akara.logger.warn("No configuration section found for %r" % (__name__, ))
paths = akara.module_config().get("paths", {})
for path, root in paths.items():
handler = MediaHandler(root)
registry.register_service(SERVICE_ID, path, handler)
def simple_service(method, service_id, path=None,
content_type=None, encoding="utf-8", writer="xml",
allow_repeated_args=False,
query_template=None,
wsgi_wrapper=None,
notify_before=None, notify_after=None):
"""Add the function as an Akara resource
These affect how the resource is registered in Akara
method - the supported HTTP method (either "GET" or "POST")
service_id - a string which identifies this service; should be a URL
path - the local URL path to the resource (must not at present
contain a '/') If None, use the function's name as the path.
query_template - An Akara URL service template (based on OpenSource; see akara.opensource)
Can be used to help consumers compose resources withing this service. The same
template is used for all HTTP methods
These control how to turn the return value into an HTTP response
content_type - the response content-type. If not specified, and if
"Content-Type" is not listed in akara.response.headers then infer
the content-type based on what the decorated function returns.
(See akara.services.convert_body for details)
encoding - Used to convert a returned Unicode string or an Amara tree
to the bytes used in the HTTP response
writer - Used to serialize the Amara tree for the HTTP response.
This must be a name which can be used as an Amara.writer.lookup.
This affects how to convert the QUERY_STRING into function call parameters
allow_repeated_args - The query string may have multiple items with the
same name, as in "?a=x&a=y&a=z&b=w". If True, this is converted into
a function call parameter like "f(a=['x','y','z'], b=['w'])". If
False then this is treated as an error. Suppose the query string
contains no repeated arguments, as in "?a=x&b=w". If
allow_repeated_args is True then the function is called as
as "f(a=['x'], b=['w'])" and if False, like "f(a='x', b='w')".
A simple_service decorated function can get request information from
akara.request and use akara.response to set the HTTP reponse code
and the HTTP response headers.
Here is an example of use:
@simple_service("GET", "http://example.com/get_date")
def date(format="%Y-%m-%d %H:%M:%S"):
'''get the current date'''
import datetime
return datetime.datetime.now().strftime(format)
which can be called with URLs like:
http://localhost:8880/date
http://localhost:8880/date?format=%25m-%25d-%25Y
Integration with other WSGI components:
The @simple_service decorator creates and returns a low-level handler
function that conforms to the WSGI calling conventions. However,
it is not safe to directly use the resulting handler with arbitrary
third-party WSGI components (e.g., to wrap the Akara handler with
an WSGI middleware component). This is because Akara handlers return
values other than sequences of byte-strings. For example, they might
return XML trees, Unicode, or other data types that would not be
correctly interpreted by other WSGI components.
To integrate other WSGI components with Akara, use the wsgi_wrapper
argument to @simple_service. For example:
def wrapper(app):
# Create an WSGI wrapper around WSGI application app
...
return wrapped_app
@simple_service("GET", "http://example.com/get_date", wsgi_wrapper=wrapper)
def date(format):
...
When specified, Akara will do the following:
- Arrange to have the wsgi_wrapper placed at the outermost layer
of Akara's processing. That is, control will pass into
the WSGI wrapper before any Akara-specific processing related
to the @simple_service handler takes place.
- Ensure that all output returned back to the WSGI wrapper
strictly conforms to the WSGI standard (is a sequence of bytes)
The wrapper function given with wsgi_wrapper should accept a function
as input and return an WSGI application as output. This application
should be a callable that accepts (environ, start_response).
See implementation notes in the code below.
"""
_no_slashes(path)
_check_is_valid_method(method)
if method not in ("GET", "POST"):
raise ValueError(
"simple_service only supports GET and POST methods, not %s" % (method,))
def service_wrapper(func):
@functools.wraps(func)
def wrapper(environ, start_response):
try:
if environ.get("REQUEST_METHOD") != method:
if method == "GET":
raise _HTTP405(["GET"])
else:
raise _HTTP405(["POST"])
args, kwargs = _get_function_args(environ, allow_repeated_args)
except _HTTPError, err:
return err.make_wsgi_response(environ, start_response)
if args:
body = args[0]
else:
body = ""
_handle_notify_before(environ, body, notify_before)
new_request(environ)
result = func(*args, **kwargs)
result, ctype, clength = convert_body(result, content_type, encoding, writer)
send_headers(start_response, ctype, clength)
result = _handle_notify_after(environ, result, notify_after)
return result
pth = path
if pth is None:
pth = func.__name__
# Construct the default query template, if needed and possible.
qt = query_template
if qt is None and method == "GET" and not allow_repeated_args:
qt = _make_query_template(func)
if qt is not None:
qt = pth + qt
# If an wsgi_wrapper was given, wrapper the service wrapper with it
if wsgi_wrapper:
wrapper = wsgi_wrapper(wrapper)
#For purposes of inspection (not a good idea to change these otherwise you'll lose sync with the values closed over)
wrapper.content_type = content_type
wrapper.encoding = encoding
wrapper.writer = writer
registry.register_service(service_id, pth, wrapper, query_template=qt)
return wrapper
# This is a very simple implementation of conditional GET with
# the Last-Modified header. It makes media files a bit speedier
# because the files are only read off disk for the first request
# (assuming the browser/client supports conditional GET).
mtime = formatdate(os.stat(filename).st_mtime, usegmt=True)
headers = [('Last-Modified', mtime)]
if environ.get('HTTP_IF_MODIFIED_SINCE', None) == mtime:
status = '304 Not Modified'
output = ()
else:
status = '200 OK'
mime_type = mimetypes.guess_type(filename)[0]
if mime_type:
headers.append(('Content-Type', mime_type))
output = [fp.read()]
fp.close()
start_response(status, headers)
return output
import akara
if not akara.module_config():
akara.logger.warn("No configuration section found for %r" % (__name__,))
paths = akara.module_config().get("paths", {})
for path, root in paths.items():
handler = MediaHandler(root)
registry.register_service(SERVICE_ID, path, handler)
def simple_service(method,
service_id,
path=None,
content_type=None,
encoding="utf-8",
writer="xml",
allow_repeated_args=False,
query_template=None,
wsgi_wrapper=None,
notify_before=None,
notify_after=None):
"""Add the function as an Akara resource
These affect how the resource is registered in Akara
method - the supported HTTP method (either "GET" or "POST")
service_id - a string which identifies this service; should be a URL
path - the local URL path to the resource (must not at present
contain a '/') If None, use the function's name as the path.
query_template - An Akara URL service template (based on OpenSource; see akara.opensource)
Can be used to help consumers compose resources withing this service. The same
template is used for all HTTP methods
These control how to turn the return value into an HTTP response
content_type - the response content-type. If not specified, and if
"Content-Type" is not listed in akara.response.headers then infer
the content-type based on what the decorated function returns.
(See akara.services.convert_body for details)
encoding - Used to convert a returned Unicode string or an Amara tree
to the bytes used in the HTTP response
writer - Used to serialize the Amara tree for the HTTP response.
This must be a name which can be used as an Amara.writer.lookup.
This affects how to convert the QUERY_STRING into function call parameters
allow_repeated_args - The query string may have multiple items with the
same name, as in "?a=x&a=y&a=z&b=w". If True, this is converted into
a function call parameter like "f(a=['x','y','z'], b=['w'])". If
False then this is treated as an error. Suppose the query string
contains no repeated arguments, as in "?a=x&b=w". If
allow_repeated_args is True then the function is called as
as "f(a=['x'], b=['w'])" and if False, like "f(a='x', b='w')".
A simple_service decorated function can get request information from
akara.request and use akara.response to set the HTTP reponse code
and the HTTP response headers.
Here is an example of use:
@simple_service("GET", "http://example.com/get_date")
def date(format="%Y-%m-%d %H:%M:%S"):
'''get the current date'''
import datetime
return datetime.datetime.now().strftime(format)
which can be called with URLs like:
http://localhost:8880/date
http://localhost:8880/date?format=%25m-%25d-%25Y
Integration with other WSGI components:
The @simple_service decorator creates and returns a low-level handler
function that conforms to the WSGI calling conventions. However,
it is not safe to directly use the resulting handler with arbitrary
third-party WSGI components (e.g., to wrap the Akara handler with
an WSGI middleware component). This is because Akara handlers return
values other than sequences of byte-strings. For example, they might
return XML trees, Unicode, or other data types that would not be
correctly interpreted by other WSGI components.
To integrate other WSGI components with Akara, use the wsgi_wrapper
argument to @simple_service. For example:
def wrapper(app):
# Create an WSGI wrapper around WSGI application app
...
return wrapped_app
@simple_service("GET", "http://example.com/get_date", wsgi_wrapper=wrapper)
def date(format):
...
When specified, Akara will do the following:
- Arrange to have the wsgi_wrapper placed at the outermost layer
of Akara's processing. That is, control will pass into
the WSGI wrapper before any Akara-specific processing related
to the @simple_service handler takes place.
- Ensure that all output returned back to the WSGI wrapper
strictly conforms to the WSGI standard (is a sequence of bytes)
The wrapper function given with wsgi_wrapper should accept a function
as input and return an WSGI application as output. This application
should be a callable that accepts (environ, start_response).
See implementation notes in the code below.
"""
_no_slashes(path)
_check_is_valid_method(method)
if method not in ("GET", "POST"):
raise ValueError(
"simple_service only supports GET and POST methods, not %s" %
(method, ))
def service_wrapper(func):
@functools.wraps(func)
def wrapper(environ, start_response):
try:
if environ.get("REQUEST_METHOD") != method:
if method == "GET":
raise _HTTP405(["GET"])
else:
raise _HTTP405(["POST"])
args, kwargs = _get_function_args(environ, allow_repeated_args)
except _HTTPError, err:
return err.make_wsgi_response(environ, start_response)
if args:
body = args[0]
else:
body = ""
_handle_notify_before(environ, body, notify_before)
new_request(environ)
result = func(*args, **kwargs)
result, ctype, clength = convert_body(result, content_type,
encoding, writer)
send_headers(start_response, ctype, clength)
result = _handle_notify_after(environ, result, notify_after)
return result
pth = path
if pth is None:
pth = func.__name__
# Construct the default query template, if needed and possible.
qt = query_template
if qt is None and method == "GET" and not allow_repeated_args:
qt = _make_query_template(func)
if qt is not None:
qt = pth + qt
# If an wsgi_wrapper was given, wrapper the service wrapper with it
if wsgi_wrapper:
wrapper = wsgi_wrapper(wrapper)
#For purposes of inspection (not a good idea to change these otherwise you'll lose sync with the values closed over)
wrapper.content_type = content_type
wrapper.encoding = encoding
wrapper.writer = writer
registry.register_service(service_id, pth, wrapper, query_template=qt)
return wrapper
