gateway-util-urltemplate/src/main/java/org/apache/knox/gateway/util/urltemplate/Expander.java - knox - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.knox.gateway.util.urltemplate;

 import java.io.UnsupportedEncodingException;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;

 public class Expander {

   private static Params EMPTY_PARAMS = new EmptyParams();

   public static URI expand( Template template, Params params, Evaluator evaluator ) throws URISyntaxException {
     return Expander.expandToUri( template, params, evaluator );
   }

   public static URI expandToUri( Template template, Params params, Evaluator evaluator ) throws URISyntaxException {
     return new URI( expandToString( template, params, evaluator ) );
   }

   public static Template expandToTemplate( Template template, Params params, Evaluator evaluator ) throws URISyntaxException {
     //TODO: This could be much more efficient if it didn't create and then parse a string.
     return Parser.parseLiteral( expandToString( template, params, evaluator ) );
   }

   public static String expandToString( Template template, Params params, Evaluator evaluator ) {
     StringBuilder builder = new StringBuilder();
     if( params == null ) {
       params = EMPTY_PARAMS;
     }
     Set<String> names = new HashSet<>( params.getNames() );
     expandScheme( template, names, params, evaluator, builder );
     expandAuthority( template, names, params, evaluator, builder );
     expandPath( template, names, params, evaluator, builder );
     if( template.hasFragment() ) {
       StringBuilder fragment = new StringBuilder();
       expandFragment( template, names, params, evaluator, fragment );
       expandQuery( template, names, params, evaluator, builder );
       builder.append( fragment );
     } else {
       expandQuery( template, names, params, evaluator, builder );
     }
     return builder.toString();
   }

   private static void expandScheme( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
     Segment segment = template.getScheme();
     if( segment != null ) {
       expandSingleValue( template.getScheme(), names, params, evaluator, builder );
       builder.append( ":" );
     }
   }

   private static void expandAuthority( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
     if( template.hasAuthority() ) {
       if( !template.isAuthorityOnly() ) {
         builder.append( "//" );
       }
       Segment username = template.getUsername();
       Segment password = template.getPassword();
       Segment host = template.getHost();
       Segment port = template.getPort();
       expandSingleValue( username, names, params, evaluator, builder );
       if( password != null ) {
         builder.append( ":" );
         expandSingleValue( password, names, params, evaluator, builder );
       }
       if( username != null || password != null ) {
         builder.append( "@" );
       }
       if( host != null ) {
         expandSingleValue( host, names, params, evaluator, builder );
       }
       if( port != null ) {
         builder.append( ":" );
         expandSingleValue( port, names, params, evaluator, builder );
       }
     }
   }

   private static void expandPath( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
     if( template.isAbsolute() ) {
       builder.append( "/" );
     }
     List<Path> path = template.getPath();
     for( int i=0, n=path.size(); i<n; i++ ) {
       if( i > 0 ) {
         builder.append( "/" );
       }
       Path segment = path.get( i );
       String name = segment.getParamName();
       Function function = new Function( name );
       names.remove( function.getParameterName() );
       Segment.Value value = segment.getFirstValue();
       switch( value.getType() ) {
         case( Segment.STATIC ):
           String pattern = value.getOriginalPattern();
           builder.append( pattern );
           break;
         case( Segment.DEFAULT ):
         case( Segment.STAR ):
         case( Segment.GLOB ):
         case( Segment.REGEX ):
           List<String> values = function.evaluate( params, evaluator );
           expandPathValues( segment, values, builder );
           break;
       }
     }
     if( template.isDirectory() && !path.isEmpty() ) {
       builder.append( "/" );
     }
   }

   //TODO: This needs to handle multiple values but only to the limit of the segment.
   private static void expandPathValues( Path segment, List<String> values, StringBuilder builder ) {
     if( values != null && !values.isEmpty() ) {
       int type = segment.getFirstValue().getType();
       if( type == Segment.GLOB || type == Segment.DEFAULT ) {
         for( int i=0, n=values.size(); i<n; i++ ) {
           if( i > 0 ) {
             builder.append( "/" );
           }
           builder.append( values.get( i ) );
         }
       } else {
         builder.append( values.get( 0 ) );
       }
     } else {
       builder.append( segment.getFirstValue().getOriginalPattern() );
     }
   }

   private static void expandQuery( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
     AtomicInteger index = new AtomicInteger( 0 );
     expandExplicitQuery( template, names, params, evaluator, builder, index );
     expandExtraQuery( template, names, params, builder, index );
     //Kevin: I took this out because it causes '?' to be added to expanded templates when there are not query params.
 //    if( template.hasQuery() && index.get() == 0 ) {
 //      builder.append( '?' );
 //    }
   }

   private static void expandExplicitQuery( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder, AtomicInteger index ) {
     Collection<Query> query = template.getQuery().values();
     if( !query.isEmpty() ) {
       Iterator<Query> iterator = query.iterator();
       while( iterator.hasNext() ) {
         int i = index.incrementAndGet();
         if( i == 1 ) {
           builder.append( "?" );
         } else {
           builder.append( "&" );
         }
         Query segment = iterator.next();
         String queryName = segment.getQueryName();
         String paramName = segment.getParamName();
         Function function = new Function( paramName );
         names.remove( function.getParameterName() );
         for( Segment.Value value: segment.getValues() ) {
           switch( value.getType() ) {
             case( Segment.STATIC ):
               builder.append( queryName );
               String pattern = value.getOriginalPattern();
               if( pattern != null ) {
                 builder.append( "=" );
                 builder.append( pattern );
               }
               break;
             case( Segment.DEFAULT ):
             case( Segment.GLOB ):
             case( Segment.STAR ):
             case( Segment.REGEX ):
               List<String> values = function.evaluate( params, evaluator );
               expandQueryValues( segment, queryName, values, builder );
               break;
             default:
           }
         }
       }
     }
   }

   private static void expandExtraQuery( Template template, Set<String> names, Params params, StringBuilder builder, AtomicInteger index ) {
     Query extra = template.getExtra();
     if( extra != null ) {
       // Need to copy to an array because we are going to modify the set while iterating.
       String[] array = new String[ names.size() ];
       names.toArray( array );
       for( String name: array ) {
         names.remove( name );
         List<String> values = params.resolve( name );
         if( values != null ) {
           for( String value: values ) {
             int i = index.incrementAndGet();
             if( i == 1 ) {
               builder.append( "?" );
             } else {
               builder.append( "&" );
             }
             appendQueryPart(name, builder);
             if( value != null ) {
               builder.append( "=" );
               appendQueryPart(value, builder);
             }
           }
         }
       }
     }
   }

   private static void expandQueryValues( Query segment, String queryName, List<String> values, StringBuilder builder ) {
     String value;
     if( values == null || values.size() == 0 ) {
       builder.append( queryName );
     } else {
       int type = segment.getFirstValue().getType();
       if( type == Segment.GLOB || type == Segment.DEFAULT ) {
         for( int i=0, n=values.size(); i<n; i++ ) {
           if( i > 0 ) {
             builder.append( "&" );
           }
           appendQueryPart(queryName, builder);
           value = values.get( i );
           if( value != null ) {
             builder.append( "=" );
             appendQueryPart(value, builder);
           }
         }
       } else {
         appendQueryPart(queryName, builder);
         value = values.get( 0 );
         if( value != null ) {
           builder.append( "=" );
           appendQueryPart(value, builder);
         }
       }
     }
   }

   private static void appendQueryPart(String part, StringBuilder builder) {
     try {
       builder.append(URLEncoder.encode(part, StandardCharsets.UTF_8.name()));
     } catch ( UnsupportedEncodingException e ) {
       builder.append(part);
     }
   }

   private static void expandFragment( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
     if( template.hasFragment() ) {
       builder.append( "#" );
     }
     expandSingleValue( template.getFragment(), names, params, evaluator, builder );
   }

   private static void expandSingleValue( Segment segment, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
     if( segment != null ) {
       String paramName = segment.getParamName();
       Function function = new Function( paramName );
       names.remove( function.getParameterName() );
       Segment.Value value = segment.getFirstValue();
       String str;
       switch( value.getType() ) {
         case Segment.DEFAULT:
         case Segment.STAR:
         case Segment.GLOB:
         case Segment.REGEX:
           List<String> values = function.evaluate( params, evaluator );
           if( values != null && !values.isEmpty() ) {
             str = values.get( 0 );
           } else if( function.getFunctionName() != null ) {
             str = paramName;
           } else {
             str = value.getOriginalPattern();
           }
           break;
         default:
           str = value.getOriginalPattern();
           break;
       }
       builder.append( str );
     }
   }

   private static class EmptyParams implements Params {
     @Override
     public Set<String> getNames() {
       return Collections.emptySet();
     }

     @Override
     public List<String> resolve( String name ) {
       return Collections.emptyList();
     }

   }

 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.knox.gateway.util.urltemplate;

	import java.io.UnsupportedEncodingException;
	import java.net.URI;
	import java.net.URISyntaxException;
	import java.net.URLEncoder;
	import java.nio.charset.StandardCharsets;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Set;
	import java.util.concurrent.atomic.AtomicInteger;

	public class Expander {

	private static Params EMPTY_PARAMS = new EmptyParams();

	public static URI expand( Template template, Params params, Evaluator evaluator ) throws URISyntaxException {
	return Expander.expandToUri( template, params, evaluator );
	}

	public static URI expandToUri( Template template, Params params, Evaluator evaluator ) throws URISyntaxException {
	return new URI( expandToString( template, params, evaluator ) );
	}

	public static Template expandToTemplate( Template template, Params params, Evaluator evaluator ) throws URISyntaxException {
	//TODO: This could be much more efficient if it didn't create and then parse a string.
	return Parser.parseLiteral( expandToString( template, params, evaluator ) );
	}

	public static String expandToString( Template template, Params params, Evaluator evaluator ) {
	StringBuilder builder = new StringBuilder();
	if( params == null ) {
	params = EMPTY_PARAMS;
	}
	Set<String> names = new HashSet<>( params.getNames() );
	expandScheme( template, names, params, evaluator, builder );
	expandAuthority( template, names, params, evaluator, builder );
	expandPath( template, names, params, evaluator, builder );
	if( template.hasFragment() ) {
	StringBuilder fragment = new StringBuilder();
	expandFragment( template, names, params, evaluator, fragment );
	expandQuery( template, names, params, evaluator, builder );
	builder.append( fragment );
	} else {
	expandQuery( template, names, params, evaluator, builder );
	}
	return builder.toString();
	}

	private static void expandScheme( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
	Segment segment = template.getScheme();
	if( segment != null ) {
	expandSingleValue( template.getScheme(), names, params, evaluator, builder );
	builder.append( ":" );
	}
	}

	private static void expandAuthority( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
	if( template.hasAuthority() ) {
	if( !template.isAuthorityOnly() ) {
	builder.append( "//" );
	}
	Segment username = template.getUsername();
	Segment password = template.getPassword();
	Segment host = template.getHost();
	Segment port = template.getPort();
	expandSingleValue( username, names, params, evaluator, builder );
	if( password != null ) {
	builder.append( ":" );
	expandSingleValue( password, names, params, evaluator, builder );
	}
	if( username != null \|\| password != null ) {
	builder.append( "@" );
	}
	if( host != null ) {
	expandSingleValue( host, names, params, evaluator, builder );
	}
	if( port != null ) {
	builder.append( ":" );
	expandSingleValue( port, names, params, evaluator, builder );
	}
	}
	}

	private static void expandPath( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
	if( template.isAbsolute() ) {
	builder.append( "/" );
	}
	List<Path> path = template.getPath();
	for( int i=0, n=path.size(); i<n; i++ ) {
	if( i > 0 ) {
	builder.append( "/" );
	}
	Path segment = path.get( i );
	String name = segment.getParamName();
	Function function = new Function( name );
	names.remove( function.getParameterName() );
	Segment.Value value = segment.getFirstValue();
	switch( value.getType() ) {
	case( Segment.STATIC ):
	String pattern = value.getOriginalPattern();
	builder.append( pattern );
	break;
	case( Segment.DEFAULT ):
	case( Segment.STAR ):
	case( Segment.GLOB ):
	case( Segment.REGEX ):
	List<String> values = function.evaluate( params, evaluator );
	expandPathValues( segment, values, builder );
	break;
	}
	}
	if( template.isDirectory() && !path.isEmpty() ) {
	builder.append( "/" );
	}
	}

	//TODO: This needs to handle multiple values but only to the limit of the segment.
	private static void expandPathValues( Path segment, List<String> values, StringBuilder builder ) {
	if( values != null && !values.isEmpty() ) {
	int type = segment.getFirstValue().getType();
	if( type == Segment.GLOB \|\| type == Segment.DEFAULT ) {
	for( int i=0, n=values.size(); i<n; i++ ) {
	if( i > 0 ) {
	builder.append( "/" );
	}
	builder.append( values.get( i ) );
	}
	} else {
	builder.append( values.get( 0 ) );
	}
	} else {
	builder.append( segment.getFirstValue().getOriginalPattern() );
	}
	}

	private static void expandQuery( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
	AtomicInteger index = new AtomicInteger( 0 );
	expandExplicitQuery( template, names, params, evaluator, builder, index );
	expandExtraQuery( template, names, params, builder, index );
	//Kevin: I took this out because it causes '?' to be added to expanded templates when there are not query params.
	// if( template.hasQuery() && index.get() == 0 ) {
	// builder.append( '?' );
	// }
	}

	private static void expandExplicitQuery( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder, AtomicInteger index ) {
	Collection<Query> query = template.getQuery().values();
	if( !query.isEmpty() ) {
	Iterator<Query> iterator = query.iterator();
	while( iterator.hasNext() ) {
	int i = index.incrementAndGet();
	if( i == 1 ) {
	builder.append( "?" );
	} else {
	builder.append( "&" );
	}
	Query segment = iterator.next();
	String queryName = segment.getQueryName();
	String paramName = segment.getParamName();
	Function function = new Function( paramName );
	names.remove( function.getParameterName() );
	for( Segment.Value value: segment.getValues() ) {
	switch( value.getType() ) {
	case( Segment.STATIC ):
	builder.append( queryName );
	String pattern = value.getOriginalPattern();
	if( pattern != null ) {
	builder.append( "=" );
	builder.append( pattern );
	}
	break;
	case( Segment.DEFAULT ):
	case( Segment.GLOB ):
	case( Segment.STAR ):
	case( Segment.REGEX ):
	List<String> values = function.evaluate( params, evaluator );
	expandQueryValues( segment, queryName, values, builder );
	break;
	default:
	}
	}
	}
	}
	}

	private static void expandExtraQuery( Template template, Set<String> names, Params params, StringBuilder builder, AtomicInteger index ) {
	Query extra = template.getExtra();
	if( extra != null ) {
	// Need to copy to an array because we are going to modify the set while iterating.
	String[] array = new String[ names.size() ];
	names.toArray( array );
	for( String name: array ) {
	names.remove( name );
	List<String> values = params.resolve( name );
	if( values != null ) {
	for( String value: values ) {
	int i = index.incrementAndGet();
	if( i == 1 ) {
	builder.append( "?" );
	} else {
	builder.append( "&" );
	}
	appendQueryPart(name, builder);
	if( value != null ) {
	builder.append( "=" );
	appendQueryPart(value, builder);
	}
	}
	}
	}
	}
	}

	private static void expandQueryValues( Query segment, String queryName, List<String> values, StringBuilder builder ) {
	String value;
	if( values == null \|\| values.size() == 0 ) {
	builder.append( queryName );
	} else {
	int type = segment.getFirstValue().getType();
	if( type == Segment.GLOB \|\| type == Segment.DEFAULT ) {
	for( int i=0, n=values.size(); i<n; i++ ) {
	if( i > 0 ) {
	builder.append( "&" );
	}
	appendQueryPart(queryName, builder);
	value = values.get( i );
	if( value != null ) {
	builder.append( "=" );
	appendQueryPart(value, builder);
	}
	}
	} else {
	appendQueryPart(queryName, builder);
	value = values.get( 0 );
	if( value != null ) {
	builder.append( "=" );
	appendQueryPart(value, builder);
	}
	}
	}
	}

	private static void appendQueryPart(String part, StringBuilder builder) {
	try {
	builder.append(URLEncoder.encode(part, StandardCharsets.UTF_8.name()));
	} catch ( UnsupportedEncodingException e ) {
	builder.append(part);
	}
	}

	private static void expandFragment( Template template, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
	if( template.hasFragment() ) {
	builder.append( "#" );
	}
	expandSingleValue( template.getFragment(), names, params, evaluator, builder );
	}

	private static void expandSingleValue( Segment segment, Set<String> names, Params params, Evaluator evaluator, StringBuilder builder ) {
	if( segment != null ) {
	String paramName = segment.getParamName();
	Function function = new Function( paramName );
	names.remove( function.getParameterName() );
	Segment.Value value = segment.getFirstValue();
	String str;
	switch( value.getType() ) {
	case Segment.DEFAULT:
	case Segment.STAR:
	case Segment.GLOB:
	case Segment.REGEX:
	List<String> values = function.evaluate( params, evaluator );
	if( values != null && !values.isEmpty() ) {
	str = values.get( 0 );
	} else if( function.getFunctionName() != null ) {
	str = paramName;
	} else {
	str = value.getOriginalPattern();
	}
	break;
	default:
	str = value.getOriginalPattern();
	break;
	}
	builder.append( str );
	}
	}

	private static class EmptyParams implements Params {
	@Override
	public Set<String> getNames() {
	return Collections.emptySet();
	}

	@Override
	public List<String> resolve( String name ) {
	return Collections.emptyList();
	}

	}

	}