Source code for pyvo.registry.regtap

# Licensed under a 3-clause BSD style license - see LICENSE.rst
a module for basic VO Registry interactions.

A VO registry is a database of VO resources--data collections and
services--that are available for VO applications.  Typically, it is
aware of the resources from all over the world.  A registry can find
relevent data collections and services through search
queries--typically, subject-based.  The registry responds with a list
of records describing matching resources.  With a record in hand, the
application can use the information in the record to access the
resource directly.  Most often, the resource is a data service that
can be queried for individual datasets of interest.

This module provides basic, low-level access to the RegTAP Registries using
standardized TAP-based services.
import os
from ..dal import scs, sia, ssa, sla, tap, query as dalq
from ..utils.formatting import para_format_desc

__all__ = ["search", "RegistryResource", "RegistryResults", "ivoid2service"]

REGISTRY_BASEURL = os.environ.get("IVOA_REGISTRY") or ""

_service_type_map = {
    "image": "sia",
    "spectrum": "ssa",
    "scs": "conesearch",
    "line": "slap",
    "sla": "slap",
    "table": "tap"

class RegistryQuery(tap.TAPQuery):
    def execute(self):
        submit the query and return the results as a RegistryResults instance

           for errors connecting to or communicating with the service
           for errors either in the input query syntax or
           other user errors detected by the service
           for errors parsing the VOTable response
        return RegistryResults(self.execute_votable(), self.queryurl)

[docs]class RegistryResults(dalq.DALResults): """ an iterable set of results from a registry query. Each record is returned as RegistryResults """
[docs] def getrecord(self, index): """ return all the attributes of a resource record with the given index as SimpleResource instance (a dictionary-like object). Parameters ---------- index : int the zero-based index of the record """ return RegistryResource(self, index)
[docs]class RegistryResource(dalq.Record): """ a dictionary for the resource metadata returned in one record of a registry query. A SimpleResource acts as a dictionary, so in general, all attributes can be accessed by name via the [] operator, and the attribute names can by returned via the keys() function. For convenience, it also stores key values as properties; these include: """ _service = None @property def ivoid(self): """ the IVOA identifier for the resource. """ return self.get("ivoid", decode=True) @property def res_type(self): """ the resource types that characterize this resource. """ return self.get("res_type", decode=True) @property def short_name(self): """ the short name for the resource """ return self.get("short_name", decode=True) @property def res_title(self): """ the title of the resource """ return self.get("res_title", default=None, decode=True) @property def content_levels(self): """ a list of content level labels that describe the intended audience for this resource. """ return self.get("content_level", default="", decode=True).split("#") @property def res_description(self): """ the textual description of the resource. See Also -------- SimpleResource.describe """ return self.get("res_description", decode=True) @property def reference_url(self): """ URL pointing to a human-readable document describing this resource. """ return self.get("reference_url", decode=True) @property def creators(self): """ The creator(s) of the resource in the ordergiven by the resource record author """ return self.get("creator_seq", default="", decode=True).split(";") @property def content_types(self): """ list of natures or genres of the content of the resource. """ return self.get("content_type", decode=True).split("#") @property def source_format(self): """ The format of source_value. """ return self.get("source_format", decode=True) @property def region_of_regard(self): """ numeric value representing the angle, given in decimal degrees, by which a positional query against this resource should be "blurred" in order to get an appropriate match. """ return float(self.get("region_of_regard", 0)) @property def waveband(self): """ a list of names of the wavebands that the resource provides data for """ return self.get("waveband", default="", decode=True).split("#") @property def access_url(self): """ the URL that can be used to access the service resource. """ return self.get("access_url", decode=True) @property def standard_id(self): """ the IVOA standard identifier """ return self.get("standard_id", decode=True) @property def service(self): """ return an appropriate DALService subclass for this resource that can be used to search the resource. Return None if the resource is not a recognized DAL service. Currently, only Conesearch, SIA, SSA, and SLA services are supported. """ if self.access_url: for key, value in { "ivo://": scs.SCSService, "ivo://": sia.SIAService, "ivo://": ssa.SSAService, "ivo://": sla.SLAService, "ivo://": tap.TAPService, }.items(): if key in self.standard_id: self._service = value(self.access_url) return self._service
[docs] def search(self, *args, **keys): """ assuming this resource refers to a searchable service, execute a search against the resource. This is equivalent to: .. code:: python self.to_service().search(*args, **keys) The arguments provided should be appropriate for the service that the DAL service type would expect. See the documentation for the appropriate service type: ============ ========================================= Service type Use the argument syntax for ============ ========================================= catalog :py:meth:`` image :py:meth:`` spectrum :py:meth:`` line :py:meth:`` database *not yet supported* ============ ========================================= Raises ------ RuntimeError if the resource does not describe a searchable service. """ if not self.service: raise dalq.DALServiceError( "resource, {}, is not a searchable service".format( self.short_name)) return*args, **keys)
[docs] def describe(self, verbose=False, width=78, file=None): """ Print a summary description of this resource. Parameters ---------- verbose : bool If false (default), only user-oriented information is printed; if true, additional information will be printed as well. width : int Format the description with given character-width. out : writable file-like object If provided, write information to this output stream. Otherwise, it is written to standard out. """ restype = "Custom Service" stdid = self.get("standard_id", decode=True).lower() if stdid: if stdid.startswith("ivo://"): restype = "Catalog Cone-search Service" elif stdid.startswith("ivo://"): restype = "Image Data Service" elif stdid.startswith("ivo://"): restype = "Spectrum Data Service" elif stdid.startswith("ivo://"): restype = "Spectral Line Database Service" elif stdid.startswith("ivo://"): restype = "Table Access Protocol Service" print(restype, file=file) print(para_format_desc(self.res_title), file=file) print("Short Name: " + self.short_name, file=file) print("IVOA Identifier: " + self.ivoid, file=file) if self.access_url: print("Base URL: " + self.access_url, file=file) if self.res_description: print(file=file) print(para_format_desc(self.res_description), file=file) print(file=file) if self.short_name: print( para_format_desc("Subjects: {}".format(self.short_name)), file=file) if self.waveband: val = (str(v) for v in self.waveband) print( para_format_desc("Waveband Coverage: " + ", ".join(val)), file=file) if verbose: if self.standard_id: print("StandardID: " + self.standard_id, file=file) if self.reference_url: print("More info: " + self.reference_url, file=file)
[docs]def ivoid2service(ivoid, servicetype=None): """Retern service(s) for a given IVOID. The servicetype option specifies the kind of service requested (conesearch, sia, ssa, slap, or tap). By default, if none is given, a list of all matching services is returned. """ service = tap.TAPService(REGISTRY_BASEURL) results = service.run_sync(""" SELECT DISTINCT access_url, standard_id FROM rr.capability NATURAL JOIN rr.interface WHERE ivoid = '{}' """.format(tap.escape(ivoid))) services = [] ivo_cls = { "ivo://": scs.SCSService, "ivo://": sia.SIAService, "ivo://": ssa.SSAService, "ivo://": sla.SLAService, "ivo://": tap.TAPService } for result in results: thistype = result["standard_id"].decode() if thistype not in ivo_cls.keys(): # This one is not a VO service continue cls = ivo_cls[thistype] if servicetype is not None and servicetype not in thistype: # Not the type of service you want continue elif servicetype is not None: # Return only one service, the first of the requested type return(cls(result["access_url"].decode())) else: # Return a list of services services.append(cls(result["access_url"].decode())) return services