Source Code for Module roslib.srvs

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 33  # Revision $Id$ 
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 35  """ 
 36  ROS Service Description Language Spec 
 37  Implements U{http://ros.org/wiki/srv} 
 38  """ 
 39   
 40  import os 
 41  import sys 
 42   
 43  try: 
 44      from cStringIO import StringIO  # Python 2.x 
 45  except ImportError: 
 46      from io import StringIO  # Python 3.x 
 47   
 48  # don't directly use code from this, though we do depend on the 
 49  # manifest.Depend data type 
 50  import roslib.manifest 
 51  import roslib.msgs 
 52  import roslib.names 
 53  import roslib.packages 
 54  import roslib.resources 
 55   
 56  # file extension 
 57  EXT = '.srv'  # alias 
 58  SEP = '/'  # e.g. std_msgs/String 
 59  # input/output deliminator 
 60  IODELIM = '---' 
 61  COMMENTCHAR = roslib.msgs.COMMENTCHAR 
 62   
 63  VERBOSE = False 
 64   
 65   
 66  # @return: True if msg-related scripts should print verbose output 
 67 -def is_verbose(): 
 68      return VERBOSE 
 69   
 70   
 71  # set whether msg-related scripts should print verbose output 
 72 -def set_verbose(v): 
 73      global VERBOSE 
 74      VERBOSE = v 
 75   
 76   
 77 -class SrvSpecException(Exception): 
 78      pass 
 79   
 80   
 81  # msg spec representation ########################################## 
 82   
 83 -class SrvSpec(object): 
 84   
 85 -    def __init__(self, request, response, text, full_name='', short_name='', package=''): 
 86          self.request = request 
 87          self.response = response 
 88          self.text = text 
 89          self.full_name = full_name 
 90          self.short_name = short_name 
 91          self.package = package 
 92   
 93 -    def __eq__(self, other): 
 94          if not other or not isinstance(other, SrvSpec): 
 95              return False 
 96          return self.request == other.request and \ 
 97              self.response == other.response and \ 
 98              self.text == other.text and \ 
 99              self.full_name == other.full_name and \ 
100              self.short_name == other.short_name and \ 
101              self.package == other.package 
102   
103 -    def __ne__(self, other): 
104          if not other or not isinstance(other, SrvSpec): 
105              return True 
106          return not self.__eq__(other) 
107   
108 -    def __repr__(self): 
109          return 'SrvSpec[%s, %s]' % (repr(self.request), repr(self.response)) 
110   
111   
112  # srv spec loading utilities ########################################## 
113   
114  # @internal 
115  # predicate for filtering directory list. matches message files 
116 -def _srv_filter(f): 
117      return os.path.isfile(f) and f.endswith(EXT) 
118   
119   
120  # also used by doxymaker 
121 -def list_srv_types(package, include_depends): 
122      """ 
123      list all services in the specified package 
124      @param package: name of package to search 
125      @type  package: str 
126      @param include_depends: if True, will also list services in package dependencies 
127      @type  include_depends: bool 
128      @return: service type names 
129      @rtype: [str] 
130      """ 
131      types = roslib.resources.list_package_resources(package, include_depends, 'srv', _srv_filter) 
132      return [x[:-len(EXT)] for x in types] 
133   
134   
135 -def srv_file(package, type_): 
136      """ 
137      @param package: name of package .srv file is in 
138      @type  package: str 
139      @param type_: type name of service 
140      @type  type_: str 
141      @return: file path of .srv file in specified package 
142      @rtype: str 
143      """ 
144      return roslib.packages.resource_file(package, 'srv', type_+EXT) 
145   
146   
147 -def get_pkg_srv_specs(package): 
148      """ 
149      List all messages that a package contains 
150      @param depend: roslib.manifest.Depend object representing package 
151      to load messages from 
152      @type  depend: Depend 
153      @return: list of message type names and specs for package, as well as a list 
154      of message names that could not be processed. 
155      @rtype: [(str,roslib.MsgSpec), [str]] 
156      """ 
157      # almost identical to roslib.msgs.get_pkg_msg_specs 
158      types = list_srv_types(package, False) 
159      specs = []  # no fancy list comprehension as we want to show errors 
160      failures = [] 
161      for t in types: 
162          try: 
163              spec = load_from_file(srv_file(package, t), package) 
164              specs.append(spec) 
165          except Exception: 
166              failures.append(t) 
167              sys.stderr.write('ERROR: unable to load %s\n' % (t)) 
168      return specs, failures 
169   
170   
171 -def load_from_string(text, package_context='', full_name='', short_name=''): 
172      """ 
173      @param text: .msg text 
174      @type  text: str 
175      @param package_context: context to use for msgTypeName, i.e. the package name, 
176      or '' to use local naming convention. 
177      @type  package_context: str 
178      @return: Message type name and message specification 
179      @rtype: roslib.MsgSpec 
180      @raise roslib.MsgSpecException: if syntax errors or other problems are detected in file 
181      """ 
182      text_in = StringIO() 
183      text_out = StringIO() 
184      accum = text_in 
185      for l in text.split('\n'): 
186          l = l.split(COMMENTCHAR)[0].strip()  # strip comments 
187          if l.startswith(IODELIM):  # lenient, by request 
188              accum = text_out 
189          else: 
190              accum.write(l+'\n') 
191      # create separate roslib.msgs objects for each half of file 
192   
193      msg_in = roslib.msgs.load_from_string(text_in.getvalue(), package_context, '%sRequest' % (full_name), '%sRequest' % (short_name)) 
194      msg_out = roslib.msgs.load_from_string(text_out.getvalue(), package_context, '%sResponse' % (full_name), '%sResponse' % (short_name)) 
195      return SrvSpec(msg_in, msg_out, text, full_name, short_name, package_context) 
196   
197   
198 -def load_from_file(file_name, package_context=''): 
199      """ 
200      Convert the .srv representation in the file to a SrvSpec instance. 
201      @param file_name: name of file to load from 
202      @type  file_name: str 
203      @param package_context: context to use for type name, i.e. the package name, 
204      or '' to use local naming convention. 
205      @type package_context: str 
206      @return: Message type name and message specification 
207      @rtype: (str, L{SrvSpec}) 
208      @raise SrvSpecException: if syntax errors or other problems are detected in file 
209      """ 
210      if VERBOSE: 
211          if package_context: 
212              sys.stdout.write('Load spec from %s into namespace [%s]\n' % (file_name, package_context)) 
213          else: 
214              sys.stdout.write('Load spec from %s\n' % (file_name)) 
215      base_file_name = os.path.basename(file_name) 
216      type_ = base_file_name[:-len(EXT)] 
217      base_type_ = type_ 
218      # determine the type name 
219      if package_context: 
220          while package_context.endswith(SEP): 
221              package_context = package_context[:-1]  # strip message separators 
222          type_ = '%s%s%s' % (package_context, SEP, type_) 
223      if not roslib.names.is_legal_resource_name(type_): 
224          raise SrvSpecException('%s: %s is not a legal service type name' % (file_name, type_)) 
225   
226      f = open(file_name, 'r') 
227      try: 
228          text = f.read() 
229          return (type_, load_from_string(text, package_context, type_, base_type_)) 
230      finally: 
231          f.close() 
232