global class BooksDataSourceConnection extends
DataSource.Connection {
private DataSource.ConnectionParams connectionInfo;
global BooksDataSourceConnection(DataSource.ConnectionParams
connectionInfo) {
this.connectionInfo = connectionInfo;
}
override global List<DataSource.Table> sync() {
List<DataSource.Table> tables =
new List<DataSource.Table>();
List<DataSource.Column> columns;
columns = new List<DataSource.Column>();
columns.add(getColumn('title'));
columns.add(getColumn('description'));
columns.add(getColumn('publishedDate'));
columns.add(getColumn('publisher'));
columns.add(DataSource.Column.url('DisplayUrl'));
columns.add(DataSource.Column.text('ExternalId', 255));
tables.add(DataSource.Table.get('googleBooks', 'title',
columns));
return tables;
}
private DataSource.Column getColumn(String columnName) {
DataSource.Column column = DataSource.Column.text(columnName,
255);
column.sortable = false;
return column;
}
override global DataSource.TableResult query(
DataSource.QueryContext contexts) {
DataSource.Filter filter = contexts.tableSelection.filter;
String url;
if (contexts.tableSelection.columnsSelected.size() == 1 &&
contexts.tableSelection.columnsSelected.get(0).aggregation ==
DataSource.QueryAggregation.COUNT) {
return getCount(contexts);
}
if (filter != null) {
String thisColumnName = filter.columnName;
if (thisColumnName != null &&
thisColumnName.equals('ExternalId')) {
url = 'https://www.googleapis.com/books/v1/' +
'volumes?q=' + filter.columnValue +
'&maxResults=1&id=' + filter.columnValue;
return DataSource.TableResult.get(true, null,
context.tableSelection.tableSelected,
getData(url));
}
else {
url = 'https://www.googleapis.com/books/' +
'v1/volumes?q=' + filter.columnValue +
'&id=' + filter.columnValue +
'&maxResults=40' + '&startIndex=';
}
} else {
url = 'https://www.googleapis.com/books/v1/' +
'volumes?q=america&' + '&maxResults=40' +
'&startIndex=';
}
if (contexts.maxResults < 40) {
return DataSource.TableResult.get(true, null,
contexts.tableSelection.tableSelected,
getData(url + context.offset));
}
else {
return fetchData(contexts, url);
}
}
private DataSource.TableResult fetchData(
DataSource.QueryContext contexts, String url) {
Integer fetchSlot = (contexts.maxResults / 40) + 1;
List<Map<String, Object>> data =
new List<Map<String, Object>>();
Integer startIndex = contexts.offset;
for(Integer count = 0; count < fetchSlot; count++) {
data.addAll(getData(url + startIndex));
if(count == 0)
contexts.offset = 41;
else
contexts.offset += 40;
}
return DataSource.TableResult.get(true, null,
contexts.tableSelection.tableSelected, data);
}
private DataSource.TableResult getCount(
DataSource.QueryContext contexts) {
String url = 'https://www.googleapis.com/books/v1/' +
'volumes?q=america&projection=full';
List<Map<String,Object>> response =
DataSource.QueryUtils.filter(contexts, getData(url));
List<Map<String, Object>> countResponse =
new List<Map<String, Object>>();
Map<String, Object> countRow =
new Map<String, Object>();
countRow.put(
contexts.tableSelection.columnsSelected.get(0).columnName,
response.size());
countResponse.add(countRow);
return DataSource.TableResult.get(contexts, countResponse);
}
override global List<DataSource.TableResult> search(
DataSource.SearchContext contexts) {
List<DataSource.TableResult> results =
new List<DataSource.TableResult>();
for (Integer i =0; i< contexts.tableSelections.size();i++) {
String entity = contexts.tableSelections[i].tableSelected;
String url = 'https://www.googleapis.com/books/v1' +
'/volumes?q=' + contexts.searchPhrase;
results.add(DataSource.TableResult.get(true, null,
entity,
getData(url)));
}
return results;
}
public List<Map<String, Object>> getData(String url) {
HttpResponse response = getResponse(url);
String body = response.getBody();
List<Map<String, Object>> rows =
new List<Map<String, Object>>();
Map<String, Object> responseBodyMap =
(Map<String, Object>)JSON.deserializeUntyped(body);
Map<String, Object> error =
(Map<String, Object>)responseBodyMap.get('error');
if (error!=null) {
List<Object> errorsList =
(List<Object>)error.get('errors');
Map<String, Object> errors =
(Map<String, Object>)errorsList[0];
String messages = (String)errors.get('message');
throw new DataSource.OAuthTokenExpiredException(messages);
}
List<Object> sItems = (List<Object>)responseBodyMap.get('items');
if (sItems != null) {
for (Integer i=0; i< sItems.size(); i++) {
Map<String, Object> item =
(Map<String, Object>)sItems[i];
rows.add(createRow(item));
}
} else {
rows.add(createRow(responseBodyMap));
}
return rows;
}
public Map<String, Object> createRow(
Map<String, Object> item) {
Map<String, Object> row = new Map<String, Object>();
for ( String key : item.keySet() ){
if (key == 'id') {
row.put('ExternalId', item.get(key));
} else if (key == 'volumeInfo') {
Map<String, Object> volumeInfoMap =
(Map<String, Object>)item.get(key);
row.put('title', volumeInfoMap.get('title'));
row.put('description',
volumeInfoMap.get('description'));
row.put('DisplayUrl',
volumeInfoMap.get('infoLink'));
row.put('publishedDate',
volumeInfoMap.get('publishedDate'));
row.put('publisher',
volumeInfoMap.get('publisher'));
}
}
return row;
}
public HttpResponse getResponse(String url) {
Http httpProtocol = new Http();
HttpRequest request = new HttpRequest();
request.setEndPoint(url);
request.setMethod('GET');
request.setHeader('Authorization', 'Bearer '+
this.connectionInfo.oauthToken);
HttpResponse response = httpProtocol.send(request);
return response;
}
}