16/08/2015

FLOWing in the baltics

What happens when you mix an Irish, an Italian, and science?



Then you let it FLOW free!



Check here to view the full album

03/08/2015

[Spotfire] Send JMS message to EMS with IronPython script

Want to take your Spotfire analysis to the next level? What about adding an extra level of interactivity to it?

Maybe you also have a BusinessWorks or BusinessEvents engine somewhere feeding data to it, and you spot something that requires your intervention, or maybe you want to replay a flow for some reason. Sound like you need to have Spotfire communicate with those engines.

HTTP? Sure it works. What if you prefer JMS instead because you also have your own EMS server?

[APT] Fix "some indexes failed to download" error

If you ever encounter this APT error:

some indexes failed to download (E: Some index files failed to download. They have been ignored, or old ones used instead.)

It might mean that your local APT info somehow was messed up but you can easily fix this by purging it and asking APT to update it again:

sudo rm -vf /var/lib/apt/lists/*
apt-get update

[Oracle] Purge schema

Purging a schema in Oracle isn't a straightforward procedure. Usually it's better to DROP the schema or the USER and recreate it.

But if you do not have the permissions to do that, or have other restrictions preventing you to perform the operation, you might find this piece of SQL code useful:

SELECT 'drop '||object_type||' '||object_name||' '||DECODE(object_type,'TABLE', ' cascade constraints;', ';') FROM USER_OBJECTS

This will generate drop statements for ALL objects in the schema it's run on. Just execute it after connecting as the user whose schema you want to purge, then copy the output and run it as script.

[Python] HTTP POST

Here is a sample piece of code on how to issue HTTP POST requests with an XML payload from Python


 URI = 'https://httpbin.org/post'  
 PARAMETERS="<NODE>VALUE</NODE>"  
   
 from System.Net import WebRequest  
 from System.Text import Encoding  
   
 request = WebRequest.Create(URI)  
 request.ContentType = "text/xml"  
 request.Method = "POST"  
   
 bytes = Encoding.ASCII.GetBytes(PARAMETERS)  
 request.ContentLength = bytes.Length  
 reqStream = request.GetRequestStream()  
 reqStream.Write(bytes, 0, bytes.Length)  
 reqStream.Close()  
   
 response = request.GetResponse()  
 from System.IO import StreamReader  
 result = StreamReader(response.GetResponseStream()).ReadToEnd()  
 print result  

[Java] untar

Now that we know how to tar in Java, let's see how to unzip using the same Apache Commons Compress library:

 import java.io.File;  
 import java.io.FileInputStream;  
 import java.io.FileOutputStream;  
 import java.io.OutputStream;  
   
 import org.apache.commons.compress.archivers.tar.TarArchiveEntry;  
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;  
 import org.apache.commons.compress.utils.IOUtils;  
   
 public void untar(String tarlocation, String tarname, String untarlocation){   
      //method variables   
      private File tarFile;  
      private TarArchiveInputStream tar_is;  
      private FileInputStream fin;  
      private TarArchiveEntry entry;  
      private File entryDestination;  
      private OutputStream out;   
   
   
      tarFile = new File(tarlocation+tarname);  
      fin = new FileInputStream(tarFile);  
      tar_is = new TarArchiveInputStream(fin);  
      //untar  
      //for each reference, untar to untarlocation, creating directories if needed  
      while ((entry = tar_is.getNextTarEntry()) != null) {  
           entryDestination = new File(untarlocation, entry.getName());  
           //if necessary create dir structure  
           entryDestination.getParentFile().mkdirs();  
           if (entry.isDirectory())  
                entryDestination.mkdirs();  
           else {  
                try{  
                     //untar current entry  
                     out = new FileOutputStream(entryDestination);  
                     IOUtils.copy(tar_is, out);  
                }  
                catch(Exception e){  
                     throw e;  
                }  
                finally{  
                     //close streams ignoring exceptions  
                  IOUtils.closeQuietly(out);  
                  IOUtils.closeQuietly(fin);  
                  IOUtils.closeQuietly(tar_is);  
                }  
           }  
      }  
 }   

[Java] Tar file or folders

A simple way to tar a file or folder (with or without subdirectories) maintaining the folders structure is using the Apache Commons Compress library.

 import java.io.File;  
 import java.io.FileInputStream;  
 import java.io.FileOutputStream;  
 import java.io.OutputStream;  
 import java.nio.file.Files;  
   
 import org.apache.commons.compress.archivers.ArchiveOutputStream;  
 import org.apache.commons.compress.archivers.ArchiveStreamFactory;  
 import org.apache.commons.compress.archivers.tar.TarArchiveEntry;  
 import org.apache.commons.compress.utils.IOUtils;  
   
 public void tar(String location, String name, String tarlocation, String tarname){   
      //method variables   
      private OutputStream out;  
      private ArchiveOutputStream tar_out;  
      private FileInputStream tmp_fis;  
   
      //out writes the final file, tar_out creates the tar archive   
      out = new FileOutputStream(new File(tarlocation+File.separator+tarname+".tar"));   
      tar_out = new ArchiveStreamFactory().createArchiveOutputStream(ArchiveStreamFactory.TAR, out);   
      //tar it   
      File f = new File(location+File.separator+name);   
      //first time baseDir is empty   
      dotar(f, "");   
      //close archive   
      tar_out.finish();    
      out.close();   
 }   
   
 //aux method for tarring  
 private void dotar(File myFile, String baseDir) throws Exception{  
      //maintain the directory structure while tarring  
      String entryName = baseDir+myFile.getName();  
      //DO NOT do a putArchiveEntry for folders as it is not needed  
      //if it's a directory then list and tar the contents. Uses recursion for nested directories  
      if(myFile.isDirectory() == true){  
           File[] filesList = myFile.listFiles();  
           if(filesList != null){  
                for (File file : filesList) {  
                     dotar(file, entryName+File.separator);  
                }  
           }  
      }  
      else{  
           //add file  
           tmp_fis = new FileInputStream(myFile);  
           try{  
                tar_out.putArchiveEntry(new TarArchiveEntry(myFile, entryName));  
                IOUtils.copy(tmp_fis, tar_out);  
                tar_out.closeArchiveEntry();  
           }  
           catch(Exception e){  
                throw e;  
           }  
           finally{  
                if(tmp_fis != null) tmp_fis.close();  
           }  
      }  
 }   


It has to be recursive so that we can handle subdirectories correctly. The resulting tarred file will untar to the same exact folder structure originally tarred. If you pass the location and tarlocation parameters with the path separator already appended, there's no need to concatenate File.separator in the code.