Standalone Mode

Aspire 3.0 Connectors works by implementing an interface called RepositoryAccessProvider. It specifies the minimum required methods to access, fetch, and scan a given Repository. The Aspire 3.0 Connector Framework is a layer that provides common control code for Full/Incremental Crawling, Distributed Processing, Group Expansion, Schedules and the link between the Aspire Admin User Interface and the crawls, all of this by calling the RepositoryAccessProvider methods when it requires to access the Repository.

This separation of the Connector Framework and the Connectors Implementations allows a very natural usage of the Connectors Implementations outside Connector Framework and even outside Aspire at all.

Among the tasks that the RepositoryAccessProvider is responsible for, there are five main tasks

Initializing the crawl configuration or SourceInfo, from the user configuration properties
1. Initial URL, username, passwords, etc.
2. Method: newSourceInfo(AspireObject properties)
Extract the initial or root crawl items
1. The discovered items are sent into a ScanListener
2. Method: processCrawlRoot(SourceItem root, SourceInfo info, ScanListener listener)
Populate the extracted items metadata
1. Method: populate(SourceItem item, SourceInfo info, RepositoryConnection conn)
Scan a container item
1. The discovered sub-items are sent into a ScanListener
2. Method: scan(SourceItem item, SourceInfo info, RepositoryConnection conn, ScanListener listener)
Fetch the content stream for an item
1. Open an input stream of the content of each of the items if available
2. Method: getFetcher()

Putting all together is responsibility of the Connector Framework or you as a stand-alone developer of a given connector implementation.

The following guide is based on the aspire-connector-wrapper project:

Step 1

Create a Java maven project and import the following dependencies into its pom.xml file

Pom dependencies

<dependency>
   <groupId>com.searchtechnologies.aspire</groupId>
   <artifactId>aspire-connector-services</artifactId>
   <version>3.0</version>
</dependency>
<dependency>
   <groupId>com.searchtechnologies.aspire</groupId>
   <artifactId>aspire-connector-framework</artifactId>
   <version>3.0</version>
</dependency>
<dependency>
   <groupId>com.searchtechnologies.aspire</groupId>
   <artifactId>aspire-services</artifactId>
   <version>3.0</version>
</dependency>
<dependency>
   <groupId>org.osgi</groupId>
   <artifactId>org.osgi.core</artifactId>
   <version>4.2.0</version>
   <scope>provided</scope>
</dependency>
<dependency>
   <groupId>org.osgi</groupId>
   <artifactId>org.osgi.compendium</artifactId>
   <version>4.2.0</version>
   <scope>provided</scope>
</dependency>
<dependency>
   <groupId>com.searchtechnologies.aspire</groupId>
   <artifactId>THE-CONNECTOR-TO-USE</artifactId>
   <version>3.0</version>
</dependency>
<dependency>
   <groupId>com.searchtechnologies.aspire</groupId>
   <artifactId>aspire-core</artifactId>
   <version>3.0</version>
</dependency>

Step 2

Initialize the crawl and configuration objects:

Crawl Initialization

public static void main(String[] args) {  
  
    //Get the scan properties from the arguments
    String scanPropertiesFile = args[0];
    
    //Instantiate a new RepositoryAccessProvider from the connector implementation
    JobFactory.initializeForStandAloneUsage();
    
    ComponentImpl component = new SP2013RAP();
    component.initialize(emptyDom);
    RepositoryAccessProvider rap = (RepositoryAccessProvider) component;
    
    //Create a CrawlControllerImpl, as some connectors depends on it
    StandaloneCrawlController crawlCtrlImpl = new StandaloneCrawlController(rap);
    
    //Load the content-source.xml configuration into an AspireObject
    AspireObject scanProps = new AspireObject("doc");
    AspireObject scanPropsFile = AspireObject.createFromXML(new File(scanPropertiesFile));
    scanProps.add(scanPropsFile);
    
    //Create and initialize a new SourceInfo from the RAP
    SourceInfo info = rap.newSourceInfo(scanPropsFile);
    info.initialize(scanProps);
    info.setCrawlController(crawlCtrlImpl);
    crawlCtrlImpl.setSourceInfo(info);

Step 3

Start the crawl:

Start crawl call

    //execute the crawl
    crawl(rap, info, Main::downloadStream);

the crawl() method:

crawl method

  private static void crawl(RepositoryAccessProvider rap, SourceInfo info, Consumer<SourceItem> processor) throws AspireException {
    //The ScanListener which maintain the local processQueue and listen for new items to crawl
    Scanner scanner = new Scanner(rap, info);
    
    //Create the crawlRoot item to initialize the crawl from the RAP
    SourceItem crawlRoot = new SourceItem("crawlRoot");
    rap.processCrawlRoot(crawlRoot, info, scanner);
    
    //Crawls the local processQueue while it is not empty
    // when empty, it means the crawl finished
    do {
      scanner.processQueue(processor);
    } while (!scanner.isQueueEmpty());
  }

downloadStream() method:

downloadStream method

  private static void downloadStream(SourceItem item) {
    System.out.println("Item: "+item.getName());
    try {
      InputStream is = item.getContentStream();
      if (is != null) {
        FileOutputStream fos = new FileOutputStream(new File("output/"+item.getName()));
        copyStream(is, fos);
        fos.close();
        is.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

Step 4

The Scanner class:

This is where the crawl gets done when calling the processQueue() method the following happens:

The current items get moved to another queue to be iterated
For each item in the queue
1. It checks if the item is a container
2. It calls the populate method on the items that needs to be processed
3. It calls the fetcher to process the item
4. If the item was a container, call the scan() method with it (this adds more items into the queue)

Scanner class

  static class Scanner implements ScanListener {

    /**
     * The queue that receives all the new items discovered
     */
    ArrayList<SourceItem> queue;
    
    /**
     * Temporary queue used for iterate the original queue
     */
    ArrayList<SourceItem> safeQueue;
    private RepositoryAccessProvider rap;
    private SourceInfo info;
    private FetchURL fetcher;
    
    public Scanner(RepositoryAccessProvider rap, SourceInfo info) throws AspireException {
      this.rap = rap;
      this.info = info;
      queue = new ArrayList<SourceItem>();
      safeQueue = new ArrayList<SourceItem>();
      fetcher = new StandaloneFetchURL(rap);
      fetcher.initialize(emptyDom);
    }
    
    public void close() {
      fetcher.close();
    }

    @Override
    public void addItem(SourceItem item) {
      //This gets called when the RAP scanner adds an item to crawl
      queue.add(item);
    }

    @Override
    public void addItems(List<SourceItem> items) {
      //This gets called when the RAP scanner adds items to crawl
      queue.addAll(items);
    }
    
    public void processQueue(Consumer<SourceItem> processor) throws AspireException {
      
      RepositoryConnection conn = rap.newConnection(info);
      
      //Move the items from the original queue into the safeQueue
      //And clear the orignal
      safeQueue.clear();
      safeQueue.addAll(queue);
      queue.clear();
      
      for (SourceItem item : safeQueue) {
        boolean container = false;
        
        if (rap.isContainer(item, conn)) {
          container = true;
        }
        
        if (info.indexContainers() || !container) {
          rap.populate(item, info, conn);
          //Call the fetcher
          Job job = JobFactory.newInstance(item.generateJobDocument());
          job.put("sourceInfo", info);
          job.put("crawlController", info.getCrawlController());
          fetcher.process(job);
          item.setContentStream((InputStream) job.get("contentStream"));
        }
        
        if (container) {
          rap.scan(item, info, conn, this);
        }
        processor.accept(item);
      }
      safeQueue.clear();
    }
    
    public boolean isQueueEmpty() {
      return queue.size()+safeQueue.size() == 0;
    }
  }

Step 5

Fetcher class

This class is only required to extend the getComponent method to return the correct RAP object.

Fetcher class

  private static class StandaloneFetchURL extends FetchURL {

    public static final String RAP = "rap";
    RepositoryAccessProvider rap;
    
    public StandaloneFetchURL(RepositoryAccessProvider rap) {
      this.rap = rap;
    }
    
    @Override
    public Component getComponent(String path) {
      if (RAP.equals(path)) {
        return (Component)rap;
      }
      return null;
    }
  }

StandaloneCrawlController class:

This class is only for extending the getNoSQLConnection method needed by some components to return a dummy NoSQLConnection object.

StandaloneCrawlController class

  private static class StandaloneCrawlController extends CrawlControllerImpl {

    RepositoryAccessProvider rap;
    public StandaloneCrawlController(RepositoryAccessProvider rap) {
      this.rap = rap;
    }

    @Override
    public RepositoryAccessProvider getRAP() {
      return rap;
    }

    @Override
    public NoSQLConnection getNoSQLConnection(String name, AspireObject properties) {
      return new EmptyNoSQLConnection();
    }
  }

EmptyNoSQLConnection class:

Like its name suggests, it is a dummy NoSQLConnection, it doesn't really do anything.

EmptyNoSQLConnection

public class EmptyNoSQLConnection implements NoSQLConnection {

      @Override
      public String getDatabase() {
        return null;
      }

      @Override
      public String getCollection() {
        return null;
      }

      @Override
      public void add(AspireObject item) throws AspireException {
      }

      @Override
      public void update(AspireObject item, String id) throws AspireException {
      }

      @Override
      public void update(AspireObject item, AspireObject filter)
          throws AspireException {
      }

      @Override
      public void updateAll(AspireObject item, AspireObject filter)
          throws AspireException {
      }

      @Override
      public void updateOrAdd(AspireObject item, AspireObject filter)
          throws AspireException {
      }

      @Override
      public boolean delete(String id) throws AspireException {
        return false;
      }

      @Override
      public boolean delete(AspireObject filter) throws AspireException {
        return false;
      }

      @Override
      public boolean deleteAll(AspireObject filter) throws AspireException {
        return false;
      }

      @Override
      public AspireObject getOneAndUpdate(AspireObject filter,
          AspireObject update) throws AspireException {
        return null;
      }

      @Override
      public AspireObject getOne(AspireObject filter) throws AspireException {
        return null;
      }

      @Override
      public NoSQLIterable<AspireObject> getAll(AspireObject filter)
          throws AspireException {
        return null;
      }

      @Override
      public NoSQLIterable<AspireObject> getAll(AspireObject filter, int skip)
          throws AspireException {
        return null;
      }

      @Override
      public NoSQLIterable<AspireObject> getAll() throws AspireException {
        return null;
      }

      @Override
      public NoSQLIterable<AspireObject> getAll(int skip)
          throws AspireException {
        return null;
      }

      @Override
      public long size() throws AspireException {
        return 0;
      }

      @Override
      public long size(AspireObject filter) throws AspireException {
        return 0;
      }

      @Override
      public void clear() throws AspireException {
      }

      @Override
      public void close() throws AspireException {
      }

      @Override
      public AspireObject getAspireObject(Object obj) throws AspireException {
        return null;
      }

      @Override
      public void flush() {
      }

      @Override
      public void setBulkTimeout(long timeout) {
      }

      @Override
      public void setBulkSize(int size) {
      }

      @Override
      public void useBulk(boolean useBulk) {
      }

      @Override
      public AspireObject getOneAndUpdateOrAdd(AspireObject update,
          AspireObject filter) throws AspireException {
        return null;
      }

      @Override
      public AspireObject getOneAndDelete(AspireObject filter)
          throws AspireException {
        return null;
      }
}

For Legacy connectors standalone crawls see:

Connector Scanner Stage Test Harness

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