source: gsdl/trunk/runtime-src/src/oaiservr/abstractlistaction.cpp@ 16835

#include "abstractlistaction.h"
#include "recptprototools.h"

#include "oaitools.h"

//--------------------------------------------------------------------------------------------------

bool abstractlistaction::output_content(ostream &output, recptproto *protocol, oaiargs &params)
{
  bool   prevDocSeen;
  ResumptionToken *token = NULL;

  // start the call; clear down the total number of output documents
  this->outputDocs = 0;

  // We don't actually handle resumptionTokens yet; if we get one, ignore it
  if (params["resumptionToken"] != "") {
    token = new ResumptionToken(params["resumptionToken"]);
  }

  this->replyToken = NULL;

  // if we've been asked for a set, then use it!
  if (params["set"] != "") {
    // get the children of this set
    text_t gsdlSet = params["set"];
    text_t gsdlCollect = "";

    // given 'demo:CL2', toGSDL returns 'demo' in gsdlCollect and 'CL2' in gsdlSet. If there is no further
    // set specified after the name of the collection however, then gsdlSet is empty.
    oaiclassifier::toGSDL(gsdlCollect, gsdlSet);

    // If gsdlSet is empty, then the user is requesting all the identifiers for the collection, so 
    // we simply output all docs via their oai_id tag. But if a specific subset IS requested, then
    // use recurse_set() to traverse any sub classifiers to find the relevant docs.
    if(gsdlSet == ""){
      ColInfoResponse_t cinfo;
      comerror_t err;
      this->output_content_for_col(output, protocol, gsdlCollect, cinfo, err, params);
    }
    else {
      if (this->check_classifier(protocol, gsdlCollect, gsdlSet)) {
    this->recurse_set(output, protocol, gsdlCollect, gsdlSet, params, token);
      }
    }
  }
  // output all records in all hierarchies
  else {
    this->output_content_for_all(output, protocol, params);
  }

  // If - regardless of set required - no documents have been seen, throw an error.
  if (this->configuration->getOAIVersion() >= 200 && this->prevDocSeen == false) {
    errorType = "noRecordsMatch";
    this->output_error(output, errorType);

    return false;
  }

  // do a resumption token if required; errors cancel a token...
  if (this->replyToken != NULL && this->errorType == "") {
    // Don't add any whitespace around the resumption token as it can confuse harvesters/validators
    output << "  <resumptionToken>" << this->replyToken->getToken() << "</resumptionToken>" << endl;
  }

  return true;
}

//--------------------------------------------------------------------------------------------------

void abstractlistaction::output_content_for_col(ostream &output, recptproto *protocol, text_t &gsdlCollect,
                        ColInfoResponse_t &cinfo, comerror_t &err, oaiargs &params)
{ int startDoc = 0;

  text_t metadataPrefix = params["metadataPrefix"];

  // check resumption token
  if (params["resumptionToken"] != "") {
    ResumptionToken token(params["resumptionToken"]);
    if (token.getCollection() == gsdlCollect) {
      startDoc = token.getPosition() - 1; // first document is said to be 1..
      metadataPrefix = "oai_dc";  // TO DO: This should come from the resumption token
    }
  }

  // Get the OAI nodes from the info db file
  text_t oai_root_node = "oai";
  text_tset metadata;  // Must be empty for efficiency
  FilterResponse_t response;
  get_children(oai_root_node, gsdlCollect, "", metadata, false, protocol, response, *this->logout);
  
  // If numDocs is 0, do nothing - this->prevDocSeen will stay false if this is the only collection
  // looked at, or will keep whatever value it had prior to this col (ensures that if the flag has
  // been set to true by a previous collection that this won't overwrite it to be false). 
  if (response.docInfo.size() > 0) {
    int errorCount      = 0; // Count the number of errors found in the given collection

    for (long i = startDoc; i < response.docInfo.size(); ++i) {
      if (errorCount > 3) { // If num errors reaches the cut-off value, bail.
    cerr << "Error: too many records(" << errorCount << ") in the " << gsdlCollect 
         << " collection have invalid or non-existant oai_ids - skipping remainder of collection.\n";
    return;
      }
      
      text_t oai_id = "oai.";
      oai_id += i;
      
      text_t gsdl_id = oaiclassifier::getGSDL_OID(gsdlCollect, oai_id, protocol, *this->logout);
      
      if (gsdl_id == "") { // If the string is empty, then the document didn't have an oai_id, so
    ++errorCount;     // increase error count
    continue;
      }


      // Check that the item with the 0ID 'gsdl_id' has a lastmodified field that fits within
      // the required date range (if specified).
      if (this->inDateRange(params["from"], params["until"], gsdlCollect, gsdl_id, protocol, output)) {
    if (this->output_document(output, protocol, gsdlCollect, gsdl_id, metadataPrefix)) {
      // this should be an IF statement, where prevDocSeen is only set to true if the above
      // function call returns true (indicating that the doc supported the metadata prefix) but
      // for some reason this is always false. This means that if no doc in the requested set supports
      // the metadata format, the "no records match" error that should be thrown won't be...
      //
      // GRB: the above comment is no longer true; proper checks are made
      this->prevDocSeen = true;
      ++this->outputDocs;
    }
      }

      // if we've output the number of resumption documents; prepare a resumptionToken
      if (this->outputDocs == this->configuration->resumeAfter()) {
    this->replyToken = new ResumptionToken(gsdlCollect, "", "");
    this->replyToken->setPosition("", i+2);
    break;
      }
    }

    cinfo.clear(); // Clear for next collection to use (if there is one).
  }
}

//--------------------------------------------------------------------------------------------
// Returns true if at least one document record is found
void abstractlistaction::output_content_for_all(ostream &output, recptproto *protocol, oaiargs &params)
{
  ColInfoResponse_t cinfo;
  comerror_t        err;
  text_tarray       collections;
  text_t            gsdlCollect = "";
  ResumptionToken   *token = NULL;

  // get a list of the collections available
  collections = this->configuration->getCollectionsList();
  //  protocol->get_collection_list(collections, err, output); 
  
  if (params["resumptionToken"] != "") {
    token = new ResumptionToken(params["resumptionToken"]);
  }

  for(int current_col = 0; current_col < collections.size(); ++current_col){
    gsdlCollect = collections[current_col];

    // ignore all leading collections before the one that matches the resumptiontoken
    if (token != NULL &&
    token->getCollection() != gsdlCollect)
    { continue;
    }

    this->output_content_for_col(output, protocol, gsdlCollect, cinfo, err, params);

    // once we've output at least one collection, continue 
    // outputting all others until the resumption total hits
    token = NULL; 

    if (this->outputDocs == this->configuration->resumeAfter()) {
      break;
    }
  }
}

//-------------------------------------------------------------------------------------------------
// Check that the requested from/until dates don't include a time, as this would be asking for too
// fine a level of granularity, one that greenstone doesn't support. An OAI error must be thrown.
/*
bool abstractlistaction::granularityTooFine(text_t &from, text_t &until)
{
  if (from != "" && from.){
    
  }
  
}
*/
//-------------------------------------------------------------------------------------------------

bool abstractlistaction::check_classifier(recptproto *protocol, const text_t &collection,
                      const text_t &classifier)
{ text_t topClass;
  FilterResponse_t response;
  text_tset        metadata;
  ofstream         logout("oai.log", ios::app);

  // exclude false children of a top-level classifier immediately...
  if (!get_info(classifier, collection, "", metadata, false, protocol, response, logout)) {
    return false;
  }
  
  // now check the top-level parent
  metadata.insert("supportsmemberof");

  text_t::const_iterator dot = findchar(classifier.begin(), classifier.end(), '.');
  if (dot != classifier.end()) {
    topClass = substr(classifier.begin(), dot);
  }
  else {
    topClass = classifier;
  }

  if (!get_info(topClass, collection, "", metadata, false, protocol, response, logout)) {
    return false;
  }
  
  if (response.docInfo[0].metadata["supportsmemberof"].values.size() == 0) {
    return false;
  }

  if (response.docInfo[0].metadata["supportsmemberof"].values[0] != "true") {
    return false;
  }

  return true;
}

void abstractlistaction::recurse_set(ostream &output, recptproto *protocol, const text_t &collection, 
                     const text_t &classifier, oaiargs &params, ResumptionToken *resumptionToken)
{
  // metadata for this call
  FilterResponse_t response;
  text_tset        metadata;
  ofstream         logout("oai.log", ios::app);
  text_t           from = params["from"];
  text_t           until = params["until"];
  text_t           metadataPrefix = params["metadataPrefix"];
  //  ResumptionToken  resumptionToken(params["resumptionToken"]);
  int              startPos = 0;

  // This is a recursive function, and so just because the current set is empty doesn't mean we necessarily
  // want to throw a 'noRecordsMatch' error; another set (parent/sibling/child) may have had documents. It
  // is therefore not enough to check that the response object in the current iteration has no docs - we
  // must also verify that NO OTHER set has had any documents. This is done with the 'prevDocSeen' flag.
  // It is set to FALSE initially, but as soon as we see a set that isn't empty, it is set to TRUE. The 
  // 'noRecordsMatch' error will only be thrown if, after all appropriate sets have been recursed into, 
  // the 'prevDocSeen' flag is still FALSE. The function returns false if no docs were seen, allowing us to 
  // throw the noRecordsMatch error.
  
  //  bool prevDocSeen = false;

  get_children(classifier, collection, "", metadata, false, protocol, response, *this->logout);

  if (params["resumptionToken"] != "") {
    // if we're at a resumptionToken
    if (classifier == resumptionToken->getNode()) {
      startPos = resumptionToken->getPosition();
    }
    else {
      text_t fullNode = resumptionToken->getNode();
      text_t::iterator leafIter = fullNode.begin() + classifier.size();

      // if the next character isn't a dot, blow up!
      if (*leafIter != '.') {
    // fatal error;
    exit(1);
      }
      
      // get the first '.' after the current classifier point;
      text_t::iterator separator = findchar(leafIter + 1, fullNode.end(), '.');

      // now, create a new subpath
      text_t nextNode = substr(fullNode.begin(), separator);

      // seek forward; TODO: improve performance of this 
      for (int c = 0; c < response.numDocs; ++c) {
    if (response.docInfo[c].OID == nextNode) {
      startPos = c;
      break;
    }
      }
    }

    // We need to subtract one from the startPos value to turn it into an index value
    startPos--;
  }
  
  for (int c = startPos; c < response.numDocs; ++c) {
    text_t child = response.docInfo[c].OID;
    
    // distinguish classifiers and documents by checking whether OID 
    // starts with CL or not
    text_t childHead;
    text_t::const_iterator start = child.begin();
    text_t::const_iterator here  = child.begin();
    here += 2;
    childHead = substr(start, here);
    
    // documents we output now
    if (childHead != "CL") {
      // Check that the item with the 0ID 'gsdl_id' has a lastmodified field that fits
      // within the required date range (if specified)
      if (this->inDateRange(from, until, collection, child, protocol, output)) {
    // TODO: check that the document can be disseminated in the required metadataPrefix

    if (this->output_document(output, protocol, collection, child, metadataPrefix)) {
      this->prevDocSeen = true;
      ++this->outputDocs;
    }
      }
    }
    // children which are classifiers are recursed
    else {
      if (resumptionToken != NULL) {
    int depth = countchar(classifier.begin(), classifier.end(), '.');
    resumptionToken->setOffset(depth, c+2);
      }
      this->recurse_set(output, protocol, collection, child, params, resumptionToken);
    }

    if (this->outputDocs == this->configuration->resumeAfter()) {
      this->replyToken = new ResumptionToken(collection, params["set"], "");
      this->replyToken->setPosition(classifier, c+2);      
      break;
    }
  }
}