org.labkey.remoteapi.Command Maven / Gradle / Ivy
Show all versions of labkey-client-api Show documentation
/*
* Copyright (c) 2008-2017 LabKey Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.labkey.remoteapi;
import org.apache.commons.codec.EncoderException;
import org.apache.commons.codec.net.URLCodec;
import org.apache.commons.logging.LogFactory;
import org.apache.http.Header;
import org.apache.http.auth.AuthenticationException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.client.utils.URIBuilder;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
/**
* Base class for all API commands. Typically, a developer will not
* use this class directly, but will instead create one of the
* classes that extend this class. For example, to select data,
* create an instance of {@link org.labkey.remoteapi.query.SelectRowsCommand},
* which provides helpful methods for setting options and obtaining
* specific result types.
*
* However, if future versions of the LabKey Server expose new HTTP APIs
* that are not yet supported with a specialized class in this library,
* the developer may still invoke these APIs by creating an instance of the
* Command object directly, providing the controller and action name for
* the new API. Parameters may then be specified by calling the setParameters()
* method, passing a populated parameter Map<String, Object>
*
* Note that this class is not thread-safe. Do not share instances of this class
* or its descendants between threads, unless the descendant declares explicitly that
* it is thread-safe.
*
* @author Dave Stearns, LabKey Corporation
* @version 1.0
*/
public class Command
{
/**
* A constant for the official JSON content type ("application/json")
*/
public final static String CONTENT_TYPE_JSON = "application/json";
/**
* An enum of common parameter names used in API URLs.
*/
public enum CommonParameters
{
apiVersion
}
private final String _controllerName;
private final String _actionName;
private Map _parameters = null;
private Integer _timeout = null;
private double _requiredVersion = 8.3;
/**
* Constructs a new Command object for calling the specified
* API action on the specified controller.
* @param controllerName The name of the controller from which the action is exposed
* @param actionName The name of the action to call
*/
public Command(String controllerName, String actionName)
{
assert null != controllerName;
assert null != actionName;
_controllerName = controllerName;
_actionName = actionName;
}
/**
* Constructs a new Command from an existing command
* @param source A source Command
*/
public Command(Command source)
{
_actionName = source.getActionName();
_controllerName = source.getControllerName();
if (null != source.getParameters())
_parameters = new HashMap(source.getParameters());
_timeout = source._timeout;
_requiredVersion = source.getRequiredVersion();
}
/**
* Returns the controller name specified when constructing this object.
* @return The controller name.
*/
public String getControllerName()
{
return _controllerName;
}
/**
* Returns the action name specified when constructing this object.
* @return The action name.
*/
public String getActionName()
{
return _actionName;
}
/**
* Returns the current parameter map, or null if a map has not yet been set.
* Derived classes will typically override this method to provide a parameter
* map based on data members set by specialized setter methods.
* @return The current parameter map.
*/
public Map getParameters()
{
if (null == _parameters)
_parameters = new HashMap();
return _parameters;
}
/**
* Sets the current parameter map.
* @param parameters The parameter map to use
*/
public void setParameters(Map parameters)
{
_parameters = parameters;
}
/**
* Returns the current timeout setting in milliseconds for this Command.
* @return The current command timeout setting. Null means defer to Connection timeout. 0 means no timeout.
*/
public Integer getTimeout()
{
return _timeout;
}
/**
* Sets the timeout for this Command.
* The value of the timeout parameter should be the maximum number of milliseconds
* this command should wait for a response from the server.
* @param timeout The new timeout setting, with null meaning defer to the Connection and 0 meaning wait indefinitely.
*/
public void setTimeout(Integer timeout)
{
_timeout = timeout;
}
/**
* Executes the command in the given folder on the specified connection, and returns
* information about the response.
*
* The folderPath parameter must be a valid folder path on the server
* referenced by connection. To execute the command in the root container,
* pass null for this parameter. Note however that executing commands in the root container
* is typically useful only for administrator level operations.
*
* The command will be executed against the server, using the credentials setup
* in the connection object. If the server is invalid or the user does not
* have sufficient permissions, a CommandException will be thrown with
* the 403 (Forbidden) HTTP status code.
*
* Note that the command is executed synchronously, so the calling code will block until the
* entire response has been read from the server. To execute a command asynchronously, use
* a separate thread.
*
* If the server returns an error HTTP status code (>= 400), this method will throw
* an instance of {@link CommandException}. Use its methods to determine the cause
* of the error.
* @param connection The connection on which this command should be executed.
* @param folderPath The folder path in which to execute the command (e.g., "My Project/My Folder/My sub-folder").
* You may also pass null to execute the command in the root container (usually requires site admin permission).
* @return A CommandResponse (or derived class), which provides access to the returned text/data.
* @throws CommandException Thrown if the server returned a non-success status code.
* @throws IOException Thrown if there was an IO problem.
*/
public ResponseType execute(Connection connection, String folderPath) throws IOException, CommandException
{
// Execute the command. Throws CommandException for error responses.
try (Response response = _execute(connection, folderPath))
{
// For non-streaming Commands, read the entire response body into memory as JSON or a String.
// The json and responseText will already be parsed when checking for an exception message on small 200 responses.
JSONObject json = response._json;
String responseText = response._responseText;
String contentType = response.getContentType();
if (json == null)
{
if (null != contentType && contentType.contains(Command.CONTENT_TYPE_JSON))
{
// Read entire response body and parse into JSON object
json = (JSONObject) JSONValue.parse(new BufferedReader(new InputStreamReader(response.getInputStream())));
}
else
{
// Otherwise, read entire response body as text.
responseText = response.getText();
}
}
return createResponse(responseText, response.getStatusCode(), contentType, json);
}
}
/**
* Response class allows clients to get an InputStream, consume lazily, and close the connection when complete.
*/
protected static class Response implements Closeable
{
private final CloseableHttpResponse _httpResponse;
private final String _contentType;
private final Long _contentLength;
// The json and responseText will already be parsed when checking for an exception message on small 200 responses.
// The parsed json should not be available to the client library user since exposing the fields would make streaming responses impossible.
private String _responseText;
private JSONObject _json;
private Response(CloseableHttpResponse httpResponse, String contentType, Long contentLength)
{
_httpResponse = httpResponse;
_contentType = contentType;
_contentLength = contentLength;
}
public String getStatusText()
{
return _httpResponse.getStatusLine().getReasonPhrase();
}
public int getStatusCode()
{
return _httpResponse.getStatusLine().getStatusCode();
}
public String getContentType()
{
return _contentType;
}
public Long getContentLength()
{
return _contentLength;
}
public InputStream getInputStream() throws IOException
{
return _httpResponse.getEntity().getContent();
}
public String getText() throws IOException
{
if (_responseText != null)
return _responseText;
Scanner s = null;
try
{
// Simple InputStream -> String conversion
s = new Scanner(_httpResponse.getEntity().getContent()).useDelimiter("\\A");
return s.hasNext() ? s.next() : "";
}
finally
{
if (s != null)
s.close();
}
}
// Caller is responsible for closing the response
public void close() throws IOException
{
_httpResponse.close();
}
}
/* NOTE: Internal experimental API for handling streaming commands. */
protected Response _execute(Connection connection, String folderPath) throws CommandException, IOException
{
assert null != getControllerName() : "You must set the controller name before executing the command!";
assert null != getActionName() : "You must set the action name before executing the command!";
CloseableHttpResponse httpResponse;
final HttpUriRequest request;
try
{
//construct and initialize the HttpUriRequest
request = getHttpRequest(connection, folderPath);
LogFactory.getLog(Command.class).info("Requesting URL: " + request.getURI().toString());
//execute the request
httpResponse = connection.executeRequest(request, getTimeout());
}
catch (URISyntaxException | AuthenticationException e)
{
throw new CommandException(e.getMessage());
}
//get the content-type header
Header contentTypeHeader = httpResponse.getFirstHeader("Content-Type");
String contentType = (null == contentTypeHeader ? null : contentTypeHeader.getValue());
Header contentLengthHeader = httpResponse.getFirstHeader("Content-Length");
Long contentLength = (null == contentLengthHeader ? null : Long.parseLong(contentLengthHeader.getValue()));
Response response = new Response(httpResponse, contentType, contentLength);
checkThrowError(response);
return response;
}
protected void checkThrowError(Response response) throws IOException, CommandException
{
int status = response.getStatusCode();
// Always throw an exception if status is 4xx or 5xx.
//the HttpUriRequest should follow redirects automatically,
//so the status code could be 2xx, 4xx, or 5xx.
if (status >= 400 && status < 600)
{
throwError(response, true);
}
// Check for a 200 status but with an exception in the json response body.
// To support streaming large responses, only check for an exception if the response size is less than 4K
if (status == 200 &&
response.getContentType() != null && response.getContentType().contains(CONTENT_TYPE_JSON) &&
response.getContentLength() != null && response.getContentLength() < 4096)
{
throwError(response, false);
}
}
private void throwError(Response r, boolean throwByDefault) throws IOException, CommandException
{
//use the status text as the message by default
String message = null != r.getStatusText() ? r.getStatusText() : "(no status text)";
// This buffers the entire response in memory, which seems OK for API error responses.
String responseText = r.getText();
JSONObject json = null;
// If the content-type is json, try to parse the response text
// and extract the "exception" property from the root-level object
String contentType = r.getContentType();
if (null != contentType && contentType.contains(CONTENT_TYPE_JSON))
{
// Parse JSON
if (responseText != null && responseText.length() > 0)
{
json = (JSONObject) JSONValue.parse(responseText);
if (json != null && json.containsKey("exception"))
{
message = (String)json.get("exception");
if ("org.labkey.api.action.ApiVersionException".equals(json.get("exceptionClass")))
throw new ApiVersionException(message, r.getStatusCode(), json, responseText);
throw new CommandException(message, r.getStatusCode(), json, responseText);
}
}
}
if (throwByDefault)
throw new CommandException(message, r.getStatusCode(), json, responseText);
// If we didn't encounter an exception property on the json object, save the fully consumed text and parsed json on the Response object
r._json = json;
r._responseText = responseText;
}
/**
* Creates an instance of the response class, initialized with
* the response text, the HTTP status code, and parsed JSONObject.
*
* Override this method
* to create an instance of a different class that extends CommandResponse
* @param text The response text from the server.
* @param status The HTTP status code.
* @param contentType The Content-Type header value.
* @param json The parsed JSONObject (or null if no JSON was returned).
* @return An instance of the response object.
*/
protected ResponseType createResponse(String text, int status, String contentType, JSONObject json)
{
return (ResponseType)new CommandResponse(text, status, contentType, json, this.copy());
}
/**
* Returns the appropriate, initialized HttpUriRequest implementation.
* Extended classes may override this to change the way the HTTP method is initialized
*
* Note that this method initializes the object created by the createRequest()
* call. Extended classes should override that method to change which type of HttpUriRequest
* gets created, and this one to change how it gets initialized.
* @param connection The Connection against which the request will be executed.
* @param folderPath The folder path in which the command will be executed.
* This and the base URL from the connection will be used to construct the
* first part of the URL.
* @return The constructed HttpUriRequest instance.
* @throws CommandException Thrown if there is a problem encoding or parsing the URL
* @throws URISyntaxException Thrown if there is a problem parsing the base URL in the connection.
*/
protected HttpUriRequest getHttpRequest(Connection connection, String folderPath) throws CommandException, URISyntaxException
{
// TODO (Dave 11/11/14 -- as far as I can tell the default of the AuthSchemes is to automatically handle challenges
// method.setDoAuthentication(true);
//construct a URI from the results of the getActionUrl method
//note that this method returns an unescaped URL, so pass
//false for the second parameter to escape it
URI uri = getActionUrl(connection, folderPath);
//the query string values will need to be escaped as they are
//put into the query string, and we don't want to re-escape the
//entire thing, as the %, & and = characters will be escaped again
//so add this separately as a raw value
//(indicating that it has already been escaped)
String queryString = getQueryString();
if (null != queryString)
uri = new URIBuilder(uri).setQuery(queryString).build();
return createRequest(uri);
}
/**
* Creates the appropriate HttpUriRequest instance. Override to create something
* other than HttpGet.
* @param uri the uri to convert
* @return The HttpUriRequest instance.
*/
protected HttpUriRequest createRequest(URI uri)
{
return new HttpGet(uri);
}
/**
* Returns the portion of the URL before the query string for this command.
*
* Note that the URL returned should not be encoded, as the calling function will encode it.
*
* For example: "http://localhost:8080/labkey/MyProject/MyFolder/selectRows.api"
* @param connection The connection to use.
* @param folderPath The folder path to use.
* @return The URL
* @throws URISyntaxException if the uri constructed from the parameters is malformed
*/
protected URI getActionUrl(Connection connection, String folderPath) throws URISyntaxException
{
//start with the connection's base URL
// Use a URI so that it correctly encodes each section of the overall URI
URI uri = new URI(connection.getBaseUrl().replace('\\','/'));
StringBuilder path = new StringBuilder(uri.getPath() == null || "".equals(uri.getPath()) ? "/" : uri.getPath());
//add the controller name
String controller = getControllerName();
if (controller.charAt(0) != '/' && path.charAt(path.length() - 1) != '/')
path.append('/');
path.append(controller);
//add the folderPath (if any)
if (null != folderPath && folderPath.length() > 0)
{
String folderPathNormalized = folderPath.replace('\\', '/');
if (folderPathNormalized.charAt(0) != '/' && path.charAt(path.length() - 1) != '/')
path.append('/');
path.append(folderPathNormalized);
}
//add the action name + ".api"
String actionName = getActionName();
if (actionName.charAt(0) != '/' && path.charAt(path.length() - 1) != '/')
path.append('/');
path.append(actionName);
if (!actionName.endsWith(".api"))
path.append(".api");
return new URIBuilder(uri).setPath(path.toString()).build();
}
/**
* Returns the query string portion of the URL for this command.
*
* The parameters in the query string should be encoded to avoid parsing errors on the server.
* @return The query string
* @throws CommandException Thrown if there is a problem encoding the query string parameter names or values
*/
protected String getQueryString() throws CommandException
{
Map params = getParameters();
//add the required version if it's > 0
if (getRequiredVersion() > 0)
params.put(CommonParameters.apiVersion.name(), getRequiredVersion());
StringBuilder qstring = new StringBuilder();
URLCodec urlCodec = new URLCodec();
try
{
for (String name : params.keySet())
{
Object value = params.get(name);
if (value instanceof Collection)
{
for (Object o : ((Collection) value))
{
appendParameter(qstring, urlCodec, name, o);
}
}
else
{
appendParameter(qstring, urlCodec, name, value);
}
}
}
catch(EncoderException e)
{
throw new CommandException(e.getMessage());
}
return qstring.length() > 0 ? qstring.toString() : null;
}
private void appendParameter(StringBuilder qstring, URLCodec urlCodec, String name, Object value)
throws EncoderException
{
String strValue = null == value ? null : getParamValueAsString(value, name);
if(null != strValue)
{
if (qstring.length() > 0)
qstring.append('&');
qstring.append(urlCodec.encode(name));
qstring.append('=');
qstring.append(urlCodec.encode(strValue));
}
}
/**
* Returns an appropriate string encoding of the parameter value.
*
* Extended classes may wish to override this method to do special string encoding
* of particular parameter data types. This class will simply return the results of
* param.toString().
* @param param The parameter value
* @param name The parameter name
* @return The string form of the parameter value.
*/
@SuppressWarnings("UnusedDeclaration")
protected String getParamValueAsString(Object param, String name)
{
return param.toString();
}
/**
* Returns the required version number of this API call.
* @return The required version number
*/
public double getRequiredVersion()
{
return _requiredVersion;
}
/**
* Sets the required version number for this API call.
* By default, the required version is 8.3, meaning that
* this call requires LabKey Server version 8.3 or higher.
* Set this to a higher number to required a later
* version of the server.
* @param requiredVersion The new required version
*/
public void setRequiredVersion(double requiredVersion)
{
_requiredVersion = requiredVersion;
}
/**
* Returns a copy of this object. Derived classes should override this
* to copy their own data members
* @return A copy of this object
*/
public Command copy()
{
return new Command(this);
}
}