Source code

001package org.hl7.fhir.r5.utils;
002
003import java.io.UnsupportedEncodingException;
004import java.net.URLDecoder;
005import java.util.LinkedHashMap;
006import java.util.LinkedList;
007import java.util.List;
008import java.util.Map;
009
010import org.hl7.fhir.exceptions.FHIRException;
011import org.hl7.fhir.r5.context.IWorkerContext;
012import org.hl7.fhir.r5.model.Base;
013import org.hl7.fhir.r5.model.Bundle;
014import org.hl7.fhir.r5.model.Bundle.BundleEntryComponent;
015import org.hl7.fhir.r5.model.ExpressionNode;
016import org.hl7.fhir.r5.model.GraphDefinition;
017import org.hl7.fhir.r5.model.GraphDefinition.GraphDefinitionLinkComponent;
018import org.hl7.fhir.r5.model.Resource;
019import org.hl7.fhir.utilities.Utilities;
020import org.hl7.fhir.utilities.graphql.Argument;
021import org.hl7.fhir.utilities.graphql.EGraphEngine;
022import org.hl7.fhir.utilities.graphql.EGraphQLException;
023import org.hl7.fhir.utilities.graphql.IGraphQLStorageServices;
024import org.hl7.fhir.utilities.graphql.StringValue;
025
026public class GraphDefinitionEngine {
027
028
029  private static final String TAG_NAME = "Compiled.expression";
030  
031  private IGraphQLStorageServices services;
032  private IWorkerContext context;
033  /**
034   *  for the host to pass context into and get back on the reference resolution interface
035   */
036  private Object appInfo;
037
038  /**
039   *  the focus resource - if (there instanceof one. if (there isn"t,) there instanceof no focus
040   */
041  private Resource start;
042
043  /**
044   * The package that describes the graphQL to be executed, operation name, and variables
045   */
046  private GraphDefinition graphDefinition;
047
048  /**
049   * If the graph definition is being run to validate a grph
050   */
051  private boolean validating;
052  
053  /**
054   * where the output from executing the query instanceof going to go
055   */
056  private Bundle bundle;
057
058  private String baseURL;
059  private FHIRPathEngine engine;
060
061  public GraphDefinitionEngine(IGraphQLStorageServices services, IWorkerContext context) {
062    super();
063    this.services = services;
064    this.context = context;
065  }
066
067  public Object getAppInfo() {
068    return appInfo;
069  }
070
071  public void setAppInfo(Object appInfo) {
072    this.appInfo = appInfo;
073  }
074
075  public Resource getFocus() {
076    return start;
077  }
078
079  public void setFocus(Resource focus) {
080    this.start = focus;
081  }
082
083  public GraphDefinition getGraphDefinition() {
084    return graphDefinition;
085  }
086
087  public void setGraphDefinition(GraphDefinition graphDefinition) {
088    this.graphDefinition = graphDefinition;
089  }
090
091  public Bundle getOutput() {
092    return bundle;
093  }
094
095  public void setOutput(Bundle bundle) {
096    this.bundle = bundle;
097  }
098
099  public IGraphQLStorageServices getServices() {
100    return services;
101  }
102
103  public IWorkerContext getContext() {
104    return context;
105  }
106
107  public String getBaseURL() {
108    return baseURL;
109  }
110
111  public void setBaseURL(String baseURL) {
112    this.baseURL = baseURL;
113  }
114
115  public boolean isValidating() {
116    return validating;
117  }
118
119  public void setValidating(boolean validating) {
120    this.validating = validating;
121  }
122
123  public void execute() throws EGraphEngine, EGraphQLException, FHIRException {
124    assert services != null;
125    assert start != null;
126    assert bundle != null;
127    assert baseURL != null;
128    assert graphDefinition != null;
129    graphDefinition.checkNoModifiers("definition", "Building graph from GraphDefinition");
130
131    check(!start.fhirType().equals(graphDefinition.getStart()), "The Graph definition requires that the start (focus reosource) is "+graphDefinition.getStart()+", but instead found "+start.fhirType());
132    
133    if (!isInBundle(start)) {
134      addToBundle(start);
135    }
136    for (GraphDefinitionLinkComponent l : graphDefinition.getLink()) {
137      processLink(start.fhirType(), start, l, 1);
138    }
139  }
140
141  private void check(boolean b, String msg) {
142    if (!b) {
143      throw new FHIRException(msg);
144    }
145  }
146
147  private boolean isInBundle(Resource resource) {
148    for (BundleEntryComponent be : bundle.getEntry()) {
149      if (be.hasResource() && be.getResource().fhirType().equals(resource.fhirType()) && be.getResource().getId().equals(resource.getId())) {
150        return true;
151      }
152    }
153    return false;
154  }
155
156  private void addToBundle(Resource resource) {
157    BundleEntryComponent be = bundle.addEntry();
158    be.setFullUrl(Utilities.pathURL(baseURL, resource.fhirType(), resource.getId()));
159    be.setResource(resource);
160  }  
161
162  private void processLink(String focusPath, Resource focus, GraphDefinitionLinkComponent link, int depth) {
163    if (link.hasPath()) {
164      processLinkPath(focusPath, focus, link, depth);
165    } else {
166      processLinkTarget(focusPath, focus, link, depth);
167    }
168  }
169
170  private void processLinkPath(String focusPath, Resource focus, GraphDefinitionLinkComponent link, int depth) {
171    String path = focusPath+" -> "+link.getPath();
172    check(link.hasPath(), "Path is needed at "+path);
173    check(!link.hasSliceName(), "SliceName is not yet supported at "+path);
174    
175    ExpressionNode node;
176    if (link.getPathElement().hasUserData(TAG_NAME)) {
177        node = (ExpressionNode) link.getPathElement().getUserData(TAG_NAME);
178    } else {
179        node = engine.parse(link.getPath());
180        link.getPathElement().setUserData(TAG_NAME, node);
181    }
182    List<Base> matches = engine.evaluate(null, focus, focus, focus, node);
183    check(!validating || matches.size() >= (link.hasMin() ? link.getMin() : 0), "Link at path "+path+" requires at least "+link.getMin()+" matches, but only found "+matches.size());
184    check(!validating || matches.size() <= (link.hasMax() ?  Integer.parseInt(link.getMax()) : Integer.MAX_VALUE), "Link at path "+path+" requires at most "+link.getMax()+" matches, but found "+matches.size());
185//    for (Base sel : matches) {
186//      check(sel.fhirType().equals("Reference"), "Selected node from an expression must be a Reference"); // todo: should a URL be ok?
187//      ReferenceResolution res = services.lookup(appInfo, focus, (Reference) sel);
188//      if (res != null) {
189//        check(res.getTargetContext() != focus, "how to handle contained resources is not yet resolved"); // todo
190//        for (GraphDefinitionLinkTargetComponent tl : link.getTarget()) {
191//          if (tl.getType().equals(res.getTarget().fhirType())) {
192//            Resource r = (Resource) res.getTarget();
193//            if (!isInBundle(r)) {
194//              addToBundle(r);
195//              for (GraphDefinitionLinkComponent l : graphDefinition.getLink()) {
196//                processLink(focus.fhirType(), r, l, depth+1);
197//              }
198//            }
199//          }
200//        }
201//      }
202//    }
203  }
204  
205  private void processLinkTarget(String focusPath, Resource focus, GraphDefinitionLinkComponent link, int depth) {
206//    check(link.getTarget().size() == 1, "If there is no path, there must be one and only one target at "+focusPath);
207//    check(link.getTarget().get(0).hasType(), "If there is no path, there must be type on the target at "+focusPath);
208//    check(link.getTarget().get(0).getParams().contains("{ref}"), "If there is no path, the target must have parameters that include a parameter using {ref} at "+focusPath);
209//    String path = focusPath+" -> "+link.getTarget().get(0).getType()+"?"+link.getTarget().get(0).getParams();
210//    
211//    List<IBaseResource> list = new ArrayList<>();
212//    List<Argument> params = new ArrayList<>();
213//    parseParams(params, link.getTarget().get(0).getParams(), focus);
214//    services.listResources(appInfo, link.getTarget().get(0).getType().toCode(), params, list);
215//    check(!validating || (list.size() >= (link.hasMin() ? link.getMin() : 0)), "Link at path "+path+" requires at least "+link.getMin()+" matches, but only found "+list.size());
216//    check(!validating || (list.size() <= (link.hasMax() && !link.getMax().equals("*") ? Integer.parseInt(link.getMax()) : Integer.MAX_VALUE)), "Link at path "+path+" requires at most "+link.getMax()+" matches, but found "+list.size());
217//    for (IBaseResource res : list) {
218//      Resource r = (Resource) res;
219//      if (!isInBundle(r)) {
220//        addToBundle(r);
221//        // Grahame Grieve 17-06-2020: this seems wrong to me - why restart? 
222//        for (GraphDefinitionLinkComponent l : graphDefinition.getLink()) {
223//          processLink(start.fhirType(), start, l, depth+1);
224//        }
225//      }
226//    }
227  }
228
229    private void parseParams(List<Argument> params, String value, Resource res) {
230      boolean refed = false;
231      Map<String, List<String>> p = splitQuery(value);
232      for (String n : p.keySet()) {
233        for (String v : p.get(n)) {
234          if (v.equals("{ref}")) {
235            refed = true;
236            v = res.fhirType()+'/'+res.getId();
237          }
238          params.add(new Argument(n, new StringValue(v)));
239        }
240      }
241      check(refed, "no use of {ref} found");
242    }
243
244  public Map<String, List<String>> splitQuery(String string) {
245    final Map<String, List<String>> query_pairs = new LinkedHashMap<String, List<String>>();
246    final String[] pairs = string.split("&");
247    for (String pair : pairs) {
248      final int idx = pair.indexOf("=");
249      final String key = idx > 0 ? decode(pair.substring(0, idx), "UTF-8") : pair;
250      if (!query_pairs.containsKey(key)) {
251        query_pairs.put(key, new LinkedList<String>());
252      }
253      final String value = idx > 0 && pair.length() > idx + 1 ? decode(pair.substring(idx + 1), "UTF-8") : null;
254      query_pairs.get(key).add(value);
255    }
256    return query_pairs;
257  }
258
259  private String decode(String s, String enc) {
260    try {
261      return URLDecoder.decode(s, enc);
262    } catch (UnsupportedEncodingException e) {
263      return s;
264    }
265  }
266  
267}