private static Interpreter getInterpreter(String contextId) throws EvalError {
// Get the appropriate interpreter
Interpreter i = null;
boolean createdInterp = false;
synchronized (interpreters) { // serialize two gets of the same name
i = interpreters.get(contextId);
if (i == null) {
i = new Interpreter();
interpreters.put(contextId, i);
createdInterp = true;
}
}
if (createdInterp) {
Log.log("Created context: " + contextId + " (" + i + ")");
// Now configure stdin and stdout to capture 10k of content
// Store references to the circular buffers within the interpreter itself.
// This provides a nice place to store them plus theoretically allows
// advanced use from within the bsh environment.
// On Windows print() outputs \r\n but in XQuery that's normalized to \n
// so the 10k of Java buffer may produce less than 10k of content in XQuery!
OutputStream circularOutput = new CircularByteArrayOutputStream(10240);
PrintStream printOutput = new PrintStream(circularOutput);
i.setOut(printOutput);
i.set("mljamout", circularOutput);
OutputStream circularError = new CircularByteArrayOutputStream(10240);
PrintStream printError = new PrintStream(circularError);
i.setErr(printError);
i.set("mljamerr", circularError);
// Capture the built-in System.out and System.err also.
// (Commented out since System appears global, can't do per interpreter.)
// i.set("mljamprintout", printOutput);
// i.set("mljamprinterr", printError);
// i.eval("System.setOut(mljamprintout);");
// i.eval("System.setErr(mljamprinterr);");
// Need to expose hexdecode() and base64decode() built-in functions
i.eval("hexdecode(String s) { return com.xqdev.jam.MLJAM.hexDecode(s); }");
i.eval("base64decode(String s) { return com.xqdev.jam.MLJAM.base64Decode(s); }");
// Let's tell the context what its id is
i.set("mljamid", contextId);
}
// Update the last accessed time, used for cleaning
i.set("mljamlast", System.currentTimeMillis());
// If it's been long enough, go snooping for stale contexts
if (System.currentTimeMillis() > lastClean + CLEAN_INTERVAL) {
Log.log("Initiated periodic scan for stale context objects");
lastClean = System.currentTimeMillis();
Iterator<Interpreter> itr = interpreters.values().iterator();
while (itr.hasNext()) {
Interpreter interp = itr.next();
Long last = (Long) interp.get("mljamlast");
if (System.currentTimeMillis() > last + STALE_TIMEOUT) {
itr.remove();
Log.log("Staled context: " + interp.get("mljamid") + " (" + interp + ")");
} else if ((System.currentTimeMillis() > last + TEMP_STALE_TIMEOUT)
&& ("" + interp.get("mljamid")).startsWith("temp:")) {
itr.remove();
Log.log("Staled temp context: " + interp.get("mljamid") + " (" + interp + ")");
}
}
}
return i;
}
/**
* TODO: Decide if we want to alter the jam:start() behavior so it connects to the server as a test.
* This has the benefit that any server restart will HUP a client halfway through something because
* the context will disappear rather than be implicitly recreated to an empty state. TODO: Consider
* adding a feature so jam:start() can provide a user-specified stale-out duration for the context.
*/
public class MLJAM extends HttpServlet {
private static HashMap<String, Interpreter> interpreters = new HashMap<String, Interpreter>();
// Need to retire interpreters after some period of inactivity.
// Temporary interpreters (those w/ client assigned names) expire faster
private static long lastClean = System.currentTimeMillis();
private static long CLEAN_INTERVAL = 5 * 60 * 1000; // five minutes
private static long STALE_TIMEOUT = 60 * 60 * 1000; // one hour
private static long TEMP_STALE_TIMEOUT = 60 * 60 * 1000; // ten minutes
private static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SZ");
/*
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
*/
private static Interpreter getInterpreter(String contextId) throws EvalError {
// Get the appropriate interpreter
Interpreter i = null;
boolean createdInterp = false;
synchronized (interpreters) { // serialize two gets of the same name
i = interpreters.get(contextId);
if (i == null) {
i = new Interpreter();
interpreters.put(contextId, i);
createdInterp = true;
}
}
if (createdInterp) {
Log.log("Created context: " + contextId + " (" + i + ")");
// Now configure stdin and stdout to capture 10k of content
// Store references to the circular buffers within the interpreter itself.
// This provides a nice place to store them plus theoretically allows
// advanced use from within the bsh environment.
// On Windows print() outputs \r\n but in XQuery that's normalized to \n
// so the 10k of Java buffer may produce less than 10k of content in XQuery!
OutputStream circularOutput = new CircularByteArrayOutputStream(10240);
PrintStream printOutput = new PrintStream(circularOutput);
i.setOut(printOutput);
i.set("mljamout", circularOutput);
OutputStream circularError = new CircularByteArrayOutputStream(10240);
PrintStream printError = new PrintStream(circularError);
i.setErr(printError);
i.set("mljamerr", circularError);
// Capture the built-in System.out and System.err also.
// (Commented out since System appears global, can't do per interpreter.)
// i.set("mljamprintout", printOutput);
// i.set("mljamprinterr", printError);
// i.eval("System.setOut(mljamprintout);");
// i.eval("System.setErr(mljamprinterr);");
// Need to expose hexdecode() and base64decode() built-in functions
i.eval("hexdecode(String s) { return com.xqdev.jam.MLJAM.hexDecode(s); }");
i.eval("base64decode(String s) { return com.xqdev.jam.MLJAM.base64Decode(s); }");
// Let's tell the context what its id is
i.set("mljamid", contextId);
}
// Update the last accessed time, used for cleaning
i.set("mljamlast", System.currentTimeMillis());
// If it's been long enough, go snooping for stale contexts
if (System.currentTimeMillis() > lastClean + CLEAN_INTERVAL) {
Log.log("Initiated periodic scan for stale context objects");
lastClean = System.currentTimeMillis();
Iterator<Interpreter> itr = interpreters.values().iterator();
while (itr.hasNext()) {
Interpreter interp = itr.next();
Long last = (Long) interp.get("mljamlast");
if (System.currentTimeMillis() > last + STALE_TIMEOUT) {
itr.remove();
Log.log("Staled context: " + interp.get("mljamid") + " (" + interp + ")");
} else if ((System.currentTimeMillis() > last + TEMP_STALE_TIMEOUT)
&& ("" + interp.get("mljamid")).startsWith("temp:")) {
itr.remove();
Log.log("Staled temp context: " + interp.get("mljamid") + " (" + interp + ")");
}
}
}
return i;
}
private static void endInterpreter(String contextId) throws EvalError {
Interpreter i = interpreters.get(contextId);
if (i == null) return;
i.eval("clear();"); // can't hurt to tell bsh to clean up internally
interpreters.remove(contextId); // now wait for GC
Log.log("Destroyed context: " + contextId + " (" + i + ")");
}
private static String getBody(HttpServletRequest req) {
try {
// Try reading the post body using characters.
// This might throw an exception if something on the
// server side already called getInputStream().
// In that case we'll pull as bytes.
Reader reader = null;
try {
reader = new BufferedReader(req.getReader());
} catch (IOException e) {
reader = new BufferedReader(new InputStreamReader(req.getInputStream(), "UTF-8"));
}
StringBuffer sbuf = new StringBuffer();
char[] cbuf = new char[4096];
int count = 0;
while ((count = reader.read(cbuf)) != -1) {
sbuf.append(cbuf, 0, count);
}
return sbuf.toString();
} catch (IOException e2) {
throw new ServerProblemException("IOException in reading POST body: " + e2.getMessage());
}
}
protected void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
doPost(req, res);
}
protected void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
try {
// A good request looks like /mljam/contextid/verb?name=varname
// The extra path info includes the context id and verb
String extra = req.getPathInfo(); // "/contextid/verb"
if (extra == null || extra.equals("")) {
throw new ClientProblemException(
"Request requires a context id and verb in its extra path info");
}
String[] parts = extra.split("/"); // { "", "contextid", "verb" }
if (parts.length < 2) {
throw new ClientProblemException(
"Request requires a context id and verb in its extra path info");
} else if (parts.length < 3) {
throw new ClientProblemException("Request requires a verb in its extra path info");
}
String contextId = parts[1];
String verb = parts[2];
String method = req.getMethod();
if (method.equalsIgnoreCase("get")) {
// We have three GET verbs: get, get-stdout, get-stderr.
// These are all idempotent, while the POST verbs aren't. The get
// verb accept a "name" query string parameter. The get verb returns
// either XQuery to evaluate (indicated by x-marklogic/xquery content type)
// or a raw binary (indicated by an application/binary-encoded content type).
if (verb.equalsIgnoreCase("get")) {
String name = req.getParameter("name");
if (name == null || name.equals("")) {
throw new ClientProblemException("The get verb requires a name parameter");
}
Interpreter i = getInterpreter(contextId);
Object o = i.get(name);
if (o instanceof byte[]) {
sendBinaryResponse(res, (byte[]) o);
} else if (o instanceof String) {
sendStringResponse(res, (String) o);
} else {
sendXQueryResponse(res, o);
}
} else if (verb.equalsIgnoreCase("get-stdout")) {
Interpreter i = getInterpreter(contextId);
i.getOut().flush();
CircularByteArrayOutputStream circ = (CircularByteArrayOutputStream) i.get("mljamout");
if (circ != null) {
sendStringResponse(res, circ.toString());
circ.reset();
} else {
throw new ServerProblemException("Could not fetch mljamout from interpreter context");
}
} else if (verb.equalsIgnoreCase("get-stderr")) {
Interpreter i = getInterpreter(contextId);
i.getErr().flush();
CircularByteArrayOutputStream circ = (CircularByteArrayOutputStream) i.get("mljamerr");
if (circ != null) {
sendStringResponse(res, circ.toString());
circ.reset();
} else {
throw new ServerProblemException("Could not fetch mljamerr from interpreter context");
}
} else {
throw new ClientProblemException("Unrecognized GET verb: " + verb);
}
} else if (method.equalsIgnoreCase("post")) {
// We have six POST verbs: eval, unset, end, source, set-string, and set-binary.
// These are POST verbs because they aren't idempotent.
// The set-string, set-binary, unset, and source verbs accept a "name"
// query string parameter. The set-string and set-binary verbs accept
// a value in their post body. The eval verb accepts code in its post body.
if (verb.equalsIgnoreCase("set-string")) {
String name = req.getParameter("name");
if (name == null || name.equals("")) {
throw new ClientProblemException("The set-string verb requires a name parameter");
}
String body = getBody(req); // a value of "" is legit
Interpreter i = getInterpreter(contextId);
i.unset(name);
i.set(name, body);
sendNoResponse(res);
} else if (verb.equalsIgnoreCase("set-binary")) {
String name = req.getParameter("name");
if (name == null || name.equals("")) {
throw new ClientProblemException("The set-binary verb requires a name parameter");
}
String body = getBody(req); // a value of "" is legit
byte[] bodyBytes = hexDecode(body); // later could do this streaming for speed
Interpreter i = getInterpreter(contextId);
i.unset(name);
i.set(name, bodyBytes);
sendNoResponse(res);
} else if (verb.equalsIgnoreCase("eval")) {
String body = getBody(req);
if (body == null || body.equals("")) {
throw new ClientProblemException(
"The eval verb requires a post body containing code to eval");
}
Interpreter i = getInterpreter(contextId);
i.eval(body);
sendNoResponse(res);
} else if (verb.equalsIgnoreCase("eval-get")) {
String body = getBody(req);
if (body == null || body.equals("")) {
throw new ClientProblemException(
"The eval-get verb requires a post body containing code to eval");
}
Interpreter i = getInterpreter(contextId);
Object o = i.eval(body);
if (o instanceof byte[]) {
sendBinaryResponse(res, (byte[]) o);
} else if (o instanceof String) {
sendStringResponse(res, (String) o);
} else {
sendXQueryResponse(res, o);
}
} else if (verb.equalsIgnoreCase("unset")) {
String name = req.getParameter("name");
if (name == null || name.equals("")) {
throw new ClientProblemException("The unset verb requires a name parameter");
}
Interpreter i = getInterpreter(contextId);
i.unset(name);
sendNoResponse(res);
} else if (verb.equalsIgnoreCase("end")) {
endInterpreter(contextId);
sendNoResponse(res);
} else if (verb.equalsIgnoreCase("source")) {
String name = req.getParameter("name");
if (name == null || name.equals("")) {
throw new ClientProblemException("The source verb requires a name parameter");
}
Interpreter i = getInterpreter(contextId);
i.source(name);
sendNoResponse(res);
} else {
throw new ClientProblemException("Unrecognized POST verb: " + verb);
}
}
} catch (TargetError e) {
Throwable target = e.getTarget();
Log.log(e);
Log.log("Target: " + target);
sendServerProblemResponse(
res,
target.getClass().getName()
+ ": "
+ target.getMessage()
+ " when executing Java code: "
+ e.getErrorText()); // include full trace?
} catch (EvalError e) {
Log.log(e);
sendServerProblemResponse(
res, e.getClass().getName() + ": " + e.getMessage()); // include full trace?
} catch (ClientProblemException e) {
Log.log(e);
sendClientProblemResponse(res, e.getMessage());
} catch (ServerProblemException e) {
Log.log(e);
sendServerProblemResponse(res, e.getMessage());
}
}
private static String escapeSingleQuotes(String s) {
return s.replaceAll("'", "''");
}
public static byte[] hexDecode(String s) {
try {
return Hex.decodeHex(s.toCharArray());
} catch (DecoderException e) {
throw new ClientProblemException(
"Hex content is not valid hex: " + e.getMessage() + ": " + s);
}
}
private static String hexEncode(byte[] bytes) {
return new String(Hex.encodeHex(bytes));
}
public static byte[] base64Decode(String s) {
try {
return Base64.decodeBase64(s.getBytes("ISO-8859-1"));
} catch (UnsupportedEncodingException e) {
throw new ServerProblemException("Server does not recognize ISO-8859-1 encoding");
}
}
private static void sendClientProblemResponse(HttpServletResponse res, String s)
throws IOException {
// Commenting out the status code because we want the client to eval the error() call
// res.setStatus(HttpServletResponse.SC_BAD_REQUEST);
if (s != null && s.length() > 4096) { // Cap super long errors
s = s.substring(0, 2048) + " ...[trimmed]... " + s.substring(s.length() - 2048);
}
res.setContentType("x-marklogic/xquery; charset=UTF-8");
Writer writer = res.getWriter();
writer.write("error('" + escapeSingleQuotes(s) + "')");
writer.flush();
}
private static void sendServerProblemResponse(HttpServletResponse res, String s)
throws IOException {
// Commenting out the status code because we want the client to eval the error() call
// res.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
res.setContentType("x-marklogic/xquery; charset=UTF-8");
if (s != null && s.length() > 4096) { // Cap super long errors
s = s.substring(0, 2048) + " ...[trimmed]... " + s.substring(s.length() - 2048);
}
Writer writer = res.getWriter();
writer.write("error('" + escapeSingleQuotes(s) + "')");
writer.flush();
}
private static void sendNoResponse(HttpServletResponse res) {
res.setStatus(HttpServletResponse.SC_NO_CONTENT);
}
private static void sendBinaryResponse(HttpServletResponse res, byte[] bytes) throws IOException {
res.setContentType("application/binary-encoded");
OutputStream out = res.getOutputStream(); // care to handle errors later?
out.write(bytes);
out.flush();
}
private static void sendStringResponse(HttpServletResponse res, String s) throws IOException {
res.setContentType("text/plain; charset=UTF-8");
Writer w = res.getWriter();
w.write(s);
w.flush();
}
private static void sendXQueryResponse(HttpServletResponse res, Object o) throws IOException {
// Make sure to leave the status code alone. It defaults to 200, but sometimes
// callers of this method will have set it to a custom code.
res.setContentType("x-marklogic/xquery; charset=UTF-8");
// res.setContentType("text/plain");
Writer writer = res.getWriter(); // care to handle errors later?
if (o == null) {
writer.write("()");
} else if (o instanceof byte[]) {
writer.write("binary {'");
writer.write(hexEncode((byte[]) o));
writer.write("'}");
} else if (o instanceof Object[]) {
Object[] arr = (Object[]) o;
writer.write("(");
for (int i = 0; i < arr.length; i++) {
sendXQueryResponse(res, arr[i]);
if (i + 1 < arr.length) writer.write(", ");
}
writer.write(")");
} else if (o instanceof String) {
writer.write("'");
writer.write(escapeSingleQuotes(o.toString()));
writer.write("'");
} else if (o instanceof Integer) {
writer.write("xs:int(");
writer.write(o.toString());
writer.write(")");
} else if (o instanceof Long) {
writer.write("xs:integer(");
writer.write(o.toString());
writer.write(")");
} else if (o instanceof Float) {
Float flt = (Float) o;
writer.write("xs:float(");
if (flt.equals(Float.POSITIVE_INFINITY)) {
writer.write("'INF'");
} else if (flt.equals(Float.NEGATIVE_INFINITY)) {
writer.write("'-INF'");
} else if (flt.equals(Float.NaN)) {
writer.write("fn:number(())"); // poor man's way to write NaN
} else {
writer.write(o.toString());
}
writer.write(")");
} else if (o instanceof Double) {
Double dbl = (Double) o;
writer.write("xs:double(");
if (dbl.equals(Double.POSITIVE_INFINITY)) {
writer.write("'INF'");
} else if (dbl.equals(Double.NEGATIVE_INFINITY)) {
writer.write("'-INF'");
} else if (dbl.equals(Double.NaN)) {
writer.write("fn:number(())"); // poor man's way to write NaN
} else {
writer.write(o.toString());
}
writer.write(")");
} else if (o instanceof Boolean) {
writer.write("xs:boolean('");
writer.write(o.toString());
writer.write("')");
} else if (o instanceof BigDecimal) {
writer.write("xs:decimal(");
writer.write(o.toString());
writer.write(")");
} else if (o instanceof Date) {
// We want something like: 2006-04-30T01:28:30.499-07:00
// We format to get: 2006-04-30T01:28:30.499-0700
// Then we add in the colon
writer.write("xs:dateTime('");
String d = dateFormat.format((Date) o);
writer.write(d.substring(0, d.length() - 2));
writer.write(":");
writer.write(d.substring(d.length() - 2));
writer.write("')");
} else if (o instanceof XMLGregorianCalendar) {
XMLGregorianCalendar greg = (XMLGregorianCalendar) o;
QName type = greg.getXMLSchemaType();
if (type.equals(DatatypeConstants.DATETIME)) {
writer.write("xs:dateTime('");
} else if (type.equals(DatatypeConstants.DATE)) {
writer.write("xs:date('");
} else if (type.equals(DatatypeConstants.TIME)) {
writer.write("xs:time('");
} else if (type.equals(DatatypeConstants.GYEARMONTH)) {
writer.write("xs:gYearMonth('");
} else if (type.equals(DatatypeConstants.GMONTHDAY)) {
writer.write("xs:gMonthDay('");
} else if (type.equals(DatatypeConstants.GYEAR)) {
writer.write("xs:gYear('");
} else if (type.equals(DatatypeConstants.GMONTH)) {
writer.write("xs:gMonth('");
} else if (type.equals(DatatypeConstants.GDAY)) {
writer.write("xs:gDay('");
}
writer.write(greg.toXMLFormat());
writer.write("')");
} else if (o instanceof Duration) {
Duration dur = (Duration) o;
/*
// The following fails on Xerces
QName type = dur.getXMLSchemaType();
if (type.equals(DatatypeConstants.DURATION)) {
writer.write("xs:duration('");
}
else if (type.equals(DatatypeConstants.DURATION_DAYTIME)) {
writer.write("xdt:dayTimeDuration('");
}
else if (type.equals(DatatypeConstants.DURATION_YEARMONTH)) {
writer.write("xdt:yearMonthDuration('");
}
*/
// If no years or months, must be DURATION_DAYTIME
if (dur.getYears() == 0 && dur.getMonths() == 0) {
writer.write("xdt:dayTimeDuration('");
}
// If has years or months but nothing else, must be DURATION_YEARMONTH
else if (dur.getDays() == 0
&& dur.getHours() == 0
&& dur.getMinutes() == 0
&& dur.getSeconds() == 0) {
writer.write("xdt:yearMonthDuration('");
} else {
writer.write("xs:duration('");
}
writer.write(dur.toString());
writer.write("')");
} else if (o instanceof org.jdom.Element) {
org.jdom.Element elt = (org.jdom.Element) o;
writer.write("xdmp:unquote('");
// Because "<" in XQuery is the same as "<" I need to double escape any ampersands
writer.write(
new org.jdom.output.XMLOutputter()
.outputString(elt)
.replaceAll("&", "&")
.replaceAll("'", "''"));
writer.write("')/*"); // make sure to return the root elt
} else if (o instanceof org.jdom.Document) {
org.jdom.Document doc = (org.jdom.Document) o;
writer.write("xdmp:unquote('");
writer.write(
new org.jdom.output.XMLOutputter()
.outputString(doc)
.replaceAll("&", "&")
.replaceAll("'", "''"));
writer.write("')");
} else if (o instanceof org.jdom.Text) {
org.jdom.Text text = (org.jdom.Text) o;
writer.write("text {'");
writer.write(escapeSingleQuotes(text.getText()));
writer.write("'}");
} else if (o instanceof org.jdom.Attribute) {
// <fake xmlns:pref="http://uri.com" pref:attrname="attrvalue"/>/@*:attrname
// <fake xmlns="http://uri.com" attrname="attrvalue"/>/@*:attrname
org.jdom.Attribute attr = (org.jdom.Attribute) o;
writer.write("<fake xmlns");
if ("".equals(attr.getNamespacePrefix())) {
writer.write("=\"");
} else {
writer.write(":" + attr.getNamespacePrefix() + "=\"");
}
writer.write(attr.getNamespaceURI());
writer.write("\" ");
writer.write(attr.getQualifiedName());
writer.write("=\"");
writer.write(escapeSingleQuotes(attr.getValue()));
writer.write("\"/>/@*:");
writer.write(attr.getName());
} else if (o instanceof org.jdom.Comment) {
org.jdom.Comment com = (org.jdom.Comment) o;
writer.write("comment {'");
writer.write(escapeSingleQuotes(com.getText()));
writer.write("'}");
} else if (o instanceof org.jdom.ProcessingInstruction) {
org.jdom.ProcessingInstruction pi = (org.jdom.ProcessingInstruction) o;
writer.write("processing-instruction ");
writer.write(pi.getTarget());
writer.write(" {'");
writer.write(escapeSingleQuotes(pi.getData()));
writer.write("'}");
} else if (o instanceof QName) {
QName q = (QName) o;
writer.write("fn:expanded-QName('");
writer.write(escapeSingleQuotes(q.getNamespaceURI()));
writer.write("','");
writer.write(q.getLocalPart());
writer.write("')");
} else {
writer.write(
"error('XQuery tried to retrieve unsupported type: " + o.getClass().getName() + "')");
}
writer.flush();
}
}