Source Code for Module roslib.srvs

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 33  # Revision $Id: srvs.py 14234 2011-07-12 00:19:01Z kwc $ 
 34  # $Author: kwc $ 
 35  """ 
 36  ROS Service Description Language Spec 
 37  Implements U{http://ros.org/wiki/srv} 
 38  """ 
 39   
 40  import os 
 41  import sys 
 42  import re 
 43   
 44  try: 
 45      from cStringIO import StringIO # Python 2.x 
 46  except ImportError: 
 47      from io import StringIO # Python 3.x 
 48   
 49  import roslib.exceptions 
 50  import roslib.msgs 
 51  import roslib.names 
 52  import roslib.packages 
 53  import roslib.resources 
 54   
 55  # don't directly use code from this, though we do depend on the 
 56  # manifest.Depend data type 
 57  import roslib.manifest 
 58   
 59  ## file extension 
 60  EXT = roslib.names.SRV_EXT #alias 
 61  SEP = roslib.names.PRN_SEPARATOR #e.g. std_msgs/String 
 62  ## input/output deliminator 
 63  IODELIM   = '---' 
 64  COMMENTCHAR = roslib.msgs.COMMENTCHAR 
 65   
 66  VERBOSE = False 
 67  ## @return: True if msg-related scripts should print verbose output 
 68 -def is_verbose(): 
 69      return VERBOSE 
 70   
 71  ## set whether msg-related scripts should print verbose output 
 72 -def set_verbose(v): 
 73      global VERBOSE 
 74      VERBOSE = v 
 75   
 76 -class SrvSpecException(roslib.exceptions.ROSLibException): pass 
 77   
 78  # msg spec representation ########################################## 
 79   
 80 -class SrvSpec(object): 
 81       
 82 -    def __init__(self, request, response, text, full_name = '', short_name = '', package = ''): 
 83          self.request = request 
 84          self.response = response 
 85          self.text = text 
 86          self.full_name = full_name 
 87          self.short_name = short_name 
 88          self.package = package 
 89           
 90 -    def __eq__(self, other): 
 91          if not other or not isinstance(other, SrvSpec): 
 92              return False 
 93          return self.request == other.request and \ 
 94                 self.response == other.response and \ 
 95                 self.text == other.text and \ 
 96                 self.full_name == other.full_name and \ 
 97                 self.short_name == other.short_name and \ 
 98                 self.package == other.package 
 99       
100 -    def __ne__(self, other): 
101          if not other or not isinstance(other, SrvSpec): 
102              return True 
103          return not self.__eq__(other) 
104   
105 -    def __repr__(self): 
106          return "SrvSpec[%s, %s]"%(repr(self.request), repr(self.response)) 
107       
108  # srv spec loading utilities ########################################## 
109   
110  ## @internal 
111  ## predicate for filtering directory list. matches message files 
112 -def _srv_filter(f): 
113      return os.path.isfile(f) and f.endswith(EXT) 
114   
115  # also used by doxymaker 
116 -def list_srv_types(package, include_depends): 
117      """ 
118      list all services in the specified package 
119      @param package: name of package to search 
120      @type  package: str 
121      @param include_depends: if True, will also list services in package dependencies 
122      @type  include_depends: bool 
123      @return: service type names 
124      @rtype: [str] 
125      """ 
126      types = roslib.resources.list_package_resources(package, include_depends, roslib.packages.SRV_DIR, _srv_filter) 
127      return [x[:-len(EXT)] for x in types] 
128   
129 -def srv_file(package, type_): 
130      """ 
131      @param package: name of package .srv file is in 
132      @type  package: str 
133      @param type_: type name of service 
134      @type  type_: str 
135      @return: file path of .srv file in specified package 
136      @rtype: str 
137      """ 
138      return roslib.packages.resource_file(package, roslib.packages.SRV_DIR, type_+EXT) 
139   
140 -def get_pkg_srv_specs(package): 
141      """ 
142      List all messages that a package contains 
143      @param depend: roslib.manifest.Depend object representing package 
144      to load messages from 
145      @type  depend: Depend 
146      @return: list of message type names and specs for package, as well as a list 
147      of message names that could not be processed.  
148      @rtype: [(str,roslib.MsgSpec), [str]] 
149      """ 
150      #almost identical to roslib.msgs.get_pkg_msg_specs 
151      types = list_srv_types(package, False) 
152      specs = [] #no fancy list comprehension as we want to show errors 
153      failures = [] 
154      for t in types: 
155          try:  
156              spec = load_from_file(srv_file(package, t), package) 
157              specs.append(spec) 
158          except Exception as e: 
159              failures.append(t) 
160              sys.stderr.write("ERROR: unable to load %s\n"%(t)) 
161      return specs, failures 
162   
163 -def load_from_string(text, package_context='', full_name='', short_name=''): 
164      """ 
165      @param text: .msg text  
166      @type  text: str 
167      @param package_context: context to use for msgTypeName, i.e. the package name, 
168      or '' to use local naming convention. 
169      @type  package_context: str 
170      @return: Message type name and message specification 
171      @rtype: roslib.MsgSpec 
172      @raise roslib.MsgSpecException: if syntax errors or other problems are detected in file 
173      """ 
174      text_in  = StringIO() 
175      text_out = StringIO() 
176      accum = text_in 
177      for l in text.split('\n'): 
178          l = l.split(COMMENTCHAR)[0].strip() #strip comments         
179          if l.startswith(IODELIM): #lenient, by request 
180              accum = text_out 
181          else: 
182              accum.write(l+'\n') 
183      # create separate roslib.msgs objects for each half of file 
184       
185      msg_in = roslib.msgs.load_from_string(text_in.getvalue(), package_context, '%sRequest'%(full_name), '%sRequest'%(short_name)) 
186      msg_out = roslib.msgs.load_from_string(text_out.getvalue(), package_context, '%sResponse'%(full_name), '%sResponse'%(short_name)) 
187      return SrvSpec(msg_in, msg_out, text, full_name, short_name, package_context) 
188   
189 -def load_from_file(file_name, package_context=''): 
190      """ 
191      Convert the .srv representation in the file to a SrvSpec instance. 
192      @param file_name: name of file to load from 
193      @type  file_name: str 
194      @param package_context: context to use for type name, i.e. the package name, 
195      or '' to use local naming convention. 
196      @type package_context: str 
197      @return: Message type name and message specification 
198      @rtype: (str, L{SrvSpec}) 
199      @raise SrvSpecException: if syntax errors or other problems are detected in file 
200      """ 
201      if VERBOSE: 
202          if package_context: 
203              sys.stdout.write("Load spec from %s into namespace [%s]\n"%(file_name, package_context)) 
204          else: 
205              sys.stdout.write("Load spec from %s\n"%(file_name)) 
206      base_file_name = os.path.basename(file_name) 
207      type_ = base_file_name[:-len(EXT)] 
208      base_type_ = type_ 
209      # determine the type name 
210      if package_context: 
211          while package_context.endswith(SEP): 
212              package_context = package_context[:-1] #strip message separators 
213          type_ = "%s%s%s"%(package_context, SEP, type_) 
214      if not roslib.names.is_legal_resource_name(type_): 
215          raise SrvSpecException("%s: %s is not a legal service type name"%(file_name, type_)) 
216       
217      f = open(file_name, 'r') 
218      try: 
219          text = f.read() 
220          return (type_, load_from_string(text, package_context, type_, base_type_)) 
221      finally: 
222          f.close() 
223