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package com.google.refine.operations.column;
import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.ExecutionException;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONWriter;
import com.google.refine.browsing.Engine;
import com.google.refine.browsing.FilteredRows;
import com.google.refine.browsing.RowVisitor;
import com.google.refine.expr.EvalError;
import com.google.refine.expr.Evaluable;
import com.google.refine.expr.ExpressionUtils;
import com.google.refine.expr.MetaParser;
import com.google.refine.expr.WrappedCell;
import com.google.refine.history.HistoryEntry;
import com.google.refine.model.AbstractOperation;
import com.google.refine.model.Cell;
import com.google.refine.model.Column;
import com.google.refine.model.Project;
import com.google.refine.model.Row;
import com.google.refine.model.changes.CellAtRow;
import com.google.refine.model.changes.ColumnAdditionChange;
import com.google.refine.operations.EngineDependentOperation;
import com.google.refine.operations.OnError;
import com.google.refine.operations.OperationRegistry;
import com.google.refine.operations.cell.TextTransformOperation;
import com.google.refine.process.LongRunningProcess;
import com.google.refine.process.Process;
import com.google.refine.util.ParsingUtilities;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.LoadingCache;
import com.google.common.cache.CacheLoader;
public class ColumnAdditionByFetchingURLsOperation extends EngineDependentOperation {
final protected String _baseColumnName;
final protected String _urlExpression;
final protected OnError _onError;
final protected String _newColumnName;
final protected int _columnInsertIndex;
final protected int _delay;
final protected boolean _cacheResponses;
static public AbstractOperation reconstruct(Project project, JSONObject obj) throws Exception {
JSONObject engineConfig = obj.getJSONObject("engineConfig");
return new ColumnAdditionByFetchingURLsOperation(
engineConfig,
obj.getString("baseColumnName"),
obj.getString("urlExpression"),
TextTransformOperation.stringToOnError(obj.getString("onError")),
obj.getString("newColumnName"),
obj.getInt("columnInsertIndex"),
obj.getInt("delay"),
obj.optBoolean("cacheResponses", false) // false for retro-compatibility
);
}
public ColumnAdditionByFetchingURLsOperation(
JSONObject engineConfig,
String baseColumnName,
String urlExpression,
OnError onError,
String newColumnName,
int columnInsertIndex,
int delay,
boolean cacheResponses
) {
super(engineConfig);
_baseColumnName = baseColumnName;
_urlExpression = urlExpression;
_onError = onError;
_newColumnName = newColumnName;
_columnInsertIndex = columnInsertIndex;
_delay = delay;
_cacheResponses = cacheResponses;
}
@Override
public void write(JSONWriter writer, Properties options)
throws JSONException {
writer.object();
writer.key("op"); writer.value(OperationRegistry.s_opClassToName.get(this.getClass()));
writer.key("description"); writer.value(getBriefDescription(null));
writer.key("engineConfig"); writer.value(getEngineConfig());
writer.key("newColumnName"); writer.value(_newColumnName);
writer.key("columnInsertIndex"); writer.value(_columnInsertIndex);
writer.key("baseColumnName"); writer.value(_baseColumnName);
writer.key("urlExpression"); writer.value(_urlExpression);
writer.key("onError"); writer.value(TextTransformOperation.onErrorToString(_onError));
writer.key("delay"); writer.value(_delay);
writer.key("cacheResponses"); writer.value(_cacheResponses);
writer.endObject();
}
@Override
protected String getBriefDescription(Project project) {
return "Create column " + _newColumnName +
" at index " + _columnInsertIndex +
" by fetching URLs based on column " + _baseColumnName +
" using expression " + _urlExpression;
}
protected String createDescription(Column column, List<CellAtRow> cellsAtRows) {
return "Create new column " + _newColumnName +
", filling " + cellsAtRows.size() +
" rows by fetching URLs based on column " + column.getName() +
" and formulated as " + _urlExpression;
}
@Override
public Process createProcess(Project project, Properties options) throws Exception {
Engine engine = createEngine(project);
engine.initializeFromJSON(_engineConfig);
Evaluable eval = MetaParser.parse(_urlExpression);
return new ColumnAdditionByFetchingURLsProcess(
project,
engine,
eval,
getBriefDescription(null),
_cacheResponses
);
}
public class ColumnAdditionByFetchingURLsProcess extends LongRunningProcess implements Runnable {
final protected Project _project;
final protected Engine _engine;
final protected Evaluable _eval;
final protected long _historyEntryID;
protected int _cellIndex;
protected LoadingCache<String, Serializable> _urlCache;
public ColumnAdditionByFetchingURLsProcess(
Project project,
Engine engine,
Evaluable eval,
String description,
boolean cacheResponses
) throws JSONException {
super(description);
_project = project;
_engine = engine;
_eval = eval;
_historyEntryID = HistoryEntry.allocateID();
_urlCache = null;
if (cacheResponses) {
_urlCache = CacheBuilder.newBuilder()
.maximumSize(2048)
.expireAfterWrite(10, TimeUnit.MINUTES)
.build(
new CacheLoader<String, Serializable>() {
public Serializable load(String urlString) {
Serializable result = fetch(urlString);
try {
// Always sleep for the delay, no matter how long the
// request took. This is more responsible than substracting
// the time spend requesting the URL, because it naturally
// slows us down if the server is busy and takes a long time
// to reply.
if (_delay > 0) {
Thread.sleep(_delay);
}
} catch (InterruptedException e) {
return null;
}
return result;
}
});
}
}
@Override
public void write(JSONWriter writer, Properties options)
throws JSONException {
writer.object();
writer.key("id"); writer.value(hashCode());
writer.key("description"); writer.value(_description);
writer.key("immediate"); writer.value(false);
writer.key("status"); writer.value(_thread == null ? "pending" : (_thread.isAlive() ? "running" : "done"));
writer.key("progress"); writer.value(_progress);
writer.endObject();
}
@Override
protected Runnable getRunnable() {
return this;
}
@Override
public void run() {
Column column = _project.columnModel.getColumnByName(_baseColumnName);
if (column == null) {
_project.processManager.onFailedProcess(this, new Exception("No column named " + _baseColumnName));
return;
}
if (_project.columnModel.getColumnByName(_newColumnName) != null) {
_project.processManager.onFailedProcess(this, new Exception("Another column already named " + _newColumnName));
return;
}
List<CellAtRow> urls = new ArrayList<CellAtRow>(_project.rows.size());
FilteredRows filteredRows = _engine.getAllFilteredRows();
filteredRows.accept(_project, createRowVisitor(urls));
List<CellAtRow> responseBodies = new ArrayList<CellAtRow>(urls.size());
for (int i = 0; i < urls.size(); i++) {
CellAtRow urlData = urls.get(i);
String urlString = urlData.cell.value.toString();
Serializable response = null;
if (_urlCache != null) {
response = cachedFetch(urlString);
} else {
response = fetch(urlString);
}
if (response != null) {
CellAtRow cellAtRow = new CellAtRow(
urlData.row,
new Cell(response, null));
responseBodies.add(cellAtRow);
}
_progress = i * 100 / urls.size();
if (_canceled) {
break;
}
}
if (!_canceled) {
HistoryEntry historyEntry = new HistoryEntry(
_historyEntryID,
_project,
_description,
ColumnAdditionByFetchingURLsOperation.this,
new ColumnAdditionChange(
_newColumnName,
_columnInsertIndex,
responseBodies)
);
_project.history.addEntry(historyEntry);
_project.processManager.onDoneProcess(this);
}
}
Serializable cachedFetch(String urlString) {
try {
return _urlCache.get(urlString);
} catch(ExecutionException e) {
return null;
}
}
Serializable fetch(String urlString) {
URL url = null;
try {
url = new URL(urlString);
} catch (MalformedURLException e) {
return null;
}
try {
URLConnection urlConnection = url.openConnection();
// urlConnection.setRequestProperty(_headerKey, _headerValue);
try {
InputStream is = urlConnection.getInputStream();
try {
String encoding = urlConnection.getContentEncoding();
if (encoding == null) {
String contentType = urlConnection.getContentType();
if (contentType != null) {
final String charsetEqual = "charset=";
int c = contentType.lastIndexOf(charsetEqual);
if (c > 0) {
encoding = contentType.substring(c + charsetEqual.length());
}
}
}
return ParsingUtilities.inputStreamToString(
is, (encoding == null) || ( encoding.equalsIgnoreCase("\"UTF-8\"")) ? "UTF-8" : encoding);
} finally {
is.close();
}
} catch (IOException e) {
String message;
if (urlConnection instanceof HttpURLConnection) {
int status = ((HttpURLConnection)urlConnection).getResponseCode();
String errorString = "";
InputStream errorStream = ((HttpURLConnection)urlConnection).getErrorStream();
if (errorStream != null) {
errorString = ParsingUtilities.inputStreamToString(errorStream);
}
message = String.format("HTTP error %d : %s | %s",status,
((HttpURLConnection)urlConnection).getResponseMessage(),
errorString);
} else {
message = e.toString();
}
return _onError == OnError.StoreError ?
new EvalError(message) : null;
}
} catch (Exception e) {
return _onError == OnError.StoreError ?
new EvalError(e.getMessage()) : null;
}
}
RowVisitor createRowVisitor(List<CellAtRow> cellsAtRows) {
return new RowVisitor() {
int cellIndex;
Properties bindings;
List<CellAtRow> cellsAtRows;
public RowVisitor init(List<CellAtRow> cellsAtRows) {
Column column = _project.columnModel.getColumnByName(_baseColumnName);
this.cellIndex = column.getCellIndex();
this.bindings = ExpressionUtils.createBindings(_project);
this.cellsAtRows = cellsAtRows;
return this;
}
@Override
public void start(Project project) {
// nothing to do
}
@Override
public void end(Project project) {
// nothing to do
}
@Override
public boolean visit(Project project, int rowIndex, Row row) {
Cell cell = row.getCell(cellIndex);
Cell newCell = null;
ExpressionUtils.bind(bindings, row, rowIndex, _baseColumnName, cell);
Object o = _eval.evaluate(bindings);
if (o != null) {
if (o instanceof Cell) {
newCell = (Cell) o;
} else if (o instanceof WrappedCell) {
newCell = ((WrappedCell) o).cell;
} else {
Serializable v = ExpressionUtils.wrapStorable(o);
if (ExpressionUtils.isNonBlankData(v)) {
newCell = new Cell(v.toString(), null);
}
}
}
if (newCell != null) {
cellsAtRows.add(new CellAtRow(rowIndex, newCell));
}
return false;
}
}.init(cellsAtRows);
}
}
}