Parsing different file types - java

I am learning Kotlin and facing some difficulties understanding how I can proceed
Currently I have a kml file that gets sent from the front end but now I would like to accept geoJson and store this i database -> so I need to create a function in Kotlin to validate file type and based on type return the correct object.
This the function that accepts kml file and calls parseKmlToPolygons
fun parseKmlToPolygons(file: MultipartFile, applicationConfiguration: ApplicationConfiguration): Geometry {
if (file.size > applicationConfiguration.getMaxKmlUploadFileSizeLimitInBytes()) {
throw FileUploadSizeLimitReachedException()
}
return parseMultiParFileToPolygons(file.inputStream)
}
private fun parseKmlToPolygons(content: InputStream): Geometry {
try {
val kml = Kml.unmarshal(content) ?: throw InvalidKmlException("Failed to parse the kml file")
return toGeometry(kml.feature)
} catch (ex: IllegalArgumentException) {
throw InvalidKmlException(ex.localizedMessage, ex)
} catch (ex: InvalidGeometryException) {
throw InvalidKmlException(ex.localizedMessage, ex)
}
}
So I probably need to create a function that detects a correct file, but is it ok for me to return type Any here? Also, is it possible to get the type of the file from inputStream?
private fun detectFileType():Any {
}
My apologies if I am not really clear here, all I need is to replace the function that takes kml files to be able to take either kml or geoJson
Update
//todo would be better to have detection logic separate
private fun parseKmlToPolygons(file: MultipartFile): Geometry {
val fileExtension: String = FilenameUtils.getExtension(file.originalFilename)
if (fileExtension == PolygonFileType.KML.name) {
return parseKmlToPolygons(file.inputStream)
} else if (fileExtension == PolygonFileType.GEOJSON.name) {
return parseKmlToPolygons(file.inputStream)
}
throw FormatNotSupportedException("File format is not supported")
}

Actually, what do you mean by the "file type"? Both types, geoJson and kml, are text files. They do not have any magic-number encoded defining the type. So, I see the following options:
use extension of the original file uploaded by the user. For that you could use MultipartFile.getOriginalFilename
use content type set by the FE when uploading the file. MultipartFile.getContentType. Most likely it won't work out of the box and you will need to adjust your frontend.
check actual file content. It's the most comlex option, but as the kml is xml-based and the geoJson is JSON-based it should be feasable.
and finally the simplest solution: create separate endpoints for both types.

Related

Save a variable when the server is off

In fact I am making a Minecraft plugin and I was wondering how some plugins (without using DB) manage to keep information even when the server is off.
For example if we make a grade plugin and we create a different list or we stack the players who constitute each. When the server will shut down and restart afterwards, the lists will become empty again (as I initialized them).
So I wanted to know if anyone had any idea how to keep this information.
If a plugin want to save informations only for itself, and it don't need to make it accessible from another way (a PHP website for example), you can use YAML format.
Create the config file :
File usersFile = new File(plugin.getDataFolder(), "user-data.yml");
if(!usersFile.exists()) { // don't exist
usersFile.createNewFile();
// OR you can copy file, but the plugin should contains a default file
/*try (InputStream in = plugin.getResource("user-data.yml");
OutputStream out = new FileOutputStream(usersFile)) {
ByteStreams.copy(in, out);
} catch (Exception e) {
e.printStackTrace();
}*/
}
Load the file as Yaml content :
YamlConfiguration config = YamlConfiguration.loadConfiguration(usersFile);
Edit content :
config.set(playerUUID, myVar);
Save content :
config.save(usersFile);
Also, I suggest you to make I/O async (read & write) with scheduler.
Bonus:
If you want to make ONE config file per user, and with default config, do like that :
File oneUsersFile = new File(plugin.getDataFolder(), playerUUID + ".yml");
if(!oneUsersFile.exists()) { // don't exist
try (InputStream in = plugin.getResource("my-def-file.yml");
OutputStream out = new FileOutputStream(oneUsersFile)) {
ByteStreams.copy(in, out); // copy default to current
} catch (Exception e) {
e.printStackTrace();
}
}
YamlConfiguration userConfig = YamlConfiguration.loadConfiguration(oneUsersFile);
PS: the variable plugin is the instance of your plugin, i.e. the class which extends "JavaPlugin".
You can use PersistentDataContainers:
To read data from a player, use
PersistentDataContainer p = player.getPersistentDataContainer();
int blocksBroken = p.get(new NamespacedKey(plugin, "blocks_broken"), PersistentDataType.INTEGER); // You can also use DOUBLE, STRING, etc.
The Namespaced key refers to the name or pointer to the data being stored. The PersistentDataType refers to the type of data that is being stored, which can be any Java primitive type or String. To write data to a player, use
p.set(new NamespacedKey(plugin, "blocks_broken"), PersistentDataType.INTEGER, blocksBroken + 1);

FileNotFoundException when converting image to base64 kotlin

I have a few images in folders that I want to send back to the user. To do that, I convert the images to base64 and just display them in the front-end. This works for most of the images, but for some reason I get a FileNotFound exception with this one image below.
Code: get the jobs, which contains information and a company object in it. Converting the job images works fine, but when I add the conversion for the company logo it says FileNotFound.
#GetMapping
fun getAllJobs(): ResponseEntity<*> {
return try {
val jobList: List<Job> = jobRepository.findAll()
jobList.map {
val file = FileUtils.readFileToByteArray(File("images/job/"+it.jobImage))
val companyFile = FileUtils.readFileToByteArray(File("images/company/"+it.company.logo))
it.company.logo = "data:image/jpeg;base64,"+Base64.getEncoder().encodeToString(companyFile)
it.jobImage = "data:image/jpeg;base64,"+Base64.getEncoder().encodeToString(file)
}
JsonDataResponse(HttpStatus.OK, "Retrieved lists of jobs ", jobList).createResponseEntity()
} catch (e: Exception) {
JsonResponse(HttpStatus.INTERNAL_SERVER_ERROR, e.message.toString()).createResponseEntity()
}
}
The images folder:
When I debug and I see what the map is doing, this is the first state of the job object, the logo and jobimage are just references:
After the first iteration, the images are correctly converted in both objects:
After the second iteration, I'm getting this error:

How to use OpenNLP parser models in an Android app?

I go through this link for java nlp https://www.tutorialspoint.com/opennlp/index.htm
I tried below code in android:
try {
File file = copyAssets();
// InputStream inputStream = new FileInputStream(file);
ParserModel model = new ParserModel(file);
// Creating a parser
Parser parser = ParserFactory.create(model);
// Parsing the sentence
String sentence = "Tutorialspoint is the largest tutorial library.";
Parse topParses[] = ParserTool.parseLine(sentence, parser,1);
for (Parse p : topParses) {
p.show();
}
} catch (Exception e) {
}
i download file **en-parser-chunking.bin** from internet and placed in assets of android project but code stop on third line i.e ParserModel model = new ParserModel(file); without giving any exception. Need to know how can this work in android? if its not working is there any other support for nlp in android without consuming any services?
The reason the code stalls/breaks at runtime is that you need to use an InputStream instead of a File to load the binary file resource. Most likely, the File instance is null when you "load" it the way as indicated in line 2. In theory, this constructor of ParserModelshould detect this and an IOException should be thrown. Yet, sadly, the JavaDoc of OpenNLP is not precise about this kind of situation and you are not handling this exception properly in the catch block.
Moreover, the code snippet you presented should be improved, so that you know what actually went wrong.
Therefore, loading a POSModel from within an Activity should be done differently. Here is a variant that takes care for both aspects:
AssetManager assetManager = getAssets();
InputStream in = null;
try {
in = assetManager.open("en-parser-chunking.bin");
POSModel posModel;
if(in != null) {
posModel = new POSModel(in);
if(posModel!=null) {
// From here, <posModel> is initialized and you can start playing with it...
// Creating a parser
Parser parser = ParserFactory.create(model);
// Parsing the sentence
String sentence = "Tutorialspoint is the largest tutorial library.";
Parse topParses[] = ParserTool.parseLine(sentence, parser,1);
for (Parse p : topParses) {
p.show();
}
}
else {
// resource file not found - whatever you want to do in this case
Log.w("NLP", "ParserModel could not initialized.");
}
}
else {
// resource file not found - whatever you want to do in this case
Log.w("NLP", "OpenNLP binary model file could not found in assets.");
}
}
catch (Exception ex) {
Log.e("NLP", "message: " + ex.getMessage(), ex);
// proper exception handling here...
}
finally {
if(in!=null) {
in.close();
}
}
This way, you're using an InputStream approach and at the same time you take care for proper exception and resource handling. Moreover, you can now use a Debugger in case something remains unclear with the resource path references of your model files. For reference, see the official JavaDoc of AssetManager#open(String resourceName).
Note well:
Loading OpenNLP's binary resources can consume quite a lot of memory. For this reason, it might be the case that your Android App's request to allocate the needed memory for this operation can or will not be granted by the actual runtime (i.e., smartphone) environment.
Therefore, carefully monitor the amount of requested/required RAM while posModel = new POSModel(in); is invoked.
Hope it helps.

sparkjava: Load PNG as base64 from InputStream

I have the following method to load resources as String where path is the String to the resource on my classpath (which works just fine on plain text):
try (Scanner scanner = new Scanner(MyClass.class.getResourceAsStream(path))) {
return scanner.useDelimiter("\\A").hasNext() ? scanner.next() : "";
}
Now I want to load a PNG image as a base64 String so I can send it back through sparkjava with Content-Type: image/png.
How can I do that?
Do not use any libraries, only plain old Java.
After setting the MIME type in the header with response.header("Content-Type", "image/png") (look up your MIME type here), you can use this:
try {
return Files.readAllBytes(Paths.get(MyClass.class.getResource(path).toURI()));
} catch (IOException | URISyntaxException exception) {
exception.printStackTrace();
}
return null;
Apart from that, to base64-encode a String in Java 8, you can use the java.util.Base64.Encoder class, so you'd just run the result of the method I posted in my description through
Base64.getMimeEncoder().encodeToString(resourceAsString.getBytes(StandardCharsets.UTF_8))
and send it back as response. I haven't got it to work for me though, for some odd reason. I simply used my framework's static files feature.

Convert embedded pictures in database

I have a 'small' problem. In a database documents contain a richtextfield. The richtextfield contains a profile picture of a certain contact. The problem is that this content is not saved as mime and therefore I can not calculate the url of the image.
I'm using a pojo to retrieve data from the person profile and use this in my xpage control to display its contents. I need to build a convert agent which takes the content of the richtextitem and converts it to mime to be able to calculate the url something like
http://host/database.nsf/($users)/D40FE4181F2B86CCC12579AB0047BD22/Photo/M2?OpenElement
Could someone help me with converting the contents of the richtextitem to mime? When I check for embedded objects in the rt field there are none. When I get the content of the field as stream and save it to a new richtext field using the following code. But the new field is not created somehow.
System.out.println("check if document contains a field with name "+fieldName);
if(!doc.hasItem(fieldName)){
throw new PictureConvertException("Could not locate richtextitem with name"+fieldName);
}
RichTextItem pictureField = (RichTextItem) doc.getFirstItem(fieldName);
System.out.println("Its a richtextfield..");
System.out.println("Copy field to backup field");
if(doc.hasItem("old_"+fieldName)){
doc.removeItem("old_"+fieldName);
}
pictureField.copyItemToDocument(doc, "old_"+fieldName);
// Vector embeddedPictures = pictureField.getEmbeddedObjects();
// System.out.println(doc.hasEmbedded());
// System.out.println("Retrieved embedded objects");
// if(embeddedPictures.isEmpty()){
// throw new PictureConvertException("No embedded objects could be found.");
// }
//
// EmbeddedObject photo = (EmbeddedObject) embeddedPictures.get(0);
System.out.println("Create inputstream");
//s.setConvertMime(false);
InputStream iStream = pictureField.getInputStream();
System.out.println("Create notesstream");
Stream nStream = s.createStream();
nStream.setContents(iStream);
System.out.println("Create mime entity");
MIMEEntity mEntity = doc.createMIMEEntity("PictureTest");
MIMEHeader cdheader = mEntity.createHeader("Content-Disposition");
System.out.println("Set header withfilename picture.gif");
cdheader.setHeaderVal("attachment;filename=picture.gif");
System.out.println("Setcontent type header");
MIMEHeader cidheader = mEntity.createHeader("Content-ID");
cidheader.setHeaderVal("picture.gif");
System.out.println("Set content from stream");
mEntity.setContentFromBytes(nStream, "application/gif", mEntity.ENC_IDENTITY_BINARY);
System.out.println("Save document..");
doc.save();
//s.setConvertMime(true);
System.out.println("Done");
// Clean up if we are done..
//doc.removeItem(fieldName);
Its been a little while now and I didn't go down the route of converting existing data to mime. I could not get it to work and after some more research it seemed to be unnecessary. Because the issue is about displaying images bound to a richtextbox I did some research on how to compute the url for an image and I came up with the following lines of code:
function getImageURL(doc:NotesDocument, strRTItem,strFileType){
if(doc!=null && !"".equals(strRTItem)){
var rtItem = doc.getFirstItem(strRTItem);
if(rtItem!=null){
var personelDB = doc.getParentDatabase();
var dbURL = getDBUrl(personelDB);
var imageURL:java.lang.StringBuffer = new java.lang.StringBuffer(dbURL);
if("file".equals(strFileType)){
var embeddedObjects:java.util.Vector = rtItem.getEmbeddedObjects();
if(!embeddedObjects.isEmpty()){
var file:NotesEmbeddedObject = embeddedObjects.get(0);
imageURL.append("(lookupView)\\");
imageURL.append(doc.getUniversalID());
imageURL.append("\\$File\\");
imageURL.append(file.getName());
imageURL.append("?Open");
}
}else{
imageURL.append(doc.getUniversalID());
imageURL.append("/"+strRTItem+"/");
if(rtItem instanceof lotus.domino.local.RichTextItem){
imageURL.append("0.C4?OpenElement");
}else{
imageURL.append("M2?OpenElement");
}
}
return imageURL.toString()
}
}
}
It will check if a given RT field is present. If this is the case it assumes a few things:
If there are files in the rtfield the first file is the picture to display
else it will create a specified url if the item is of type Rt otherwhise it will assume it is a mime entity and will generate another url.
Not sure if this is an answer but I can't seem to add comments yet. Have you verified that there is something in your stream?
if (stream.getBytes() != 0) {
The issue cannot be resolved "ideally" in Java.
1) if you convert to MIME, you screw up the original Notes rich text. MIME allows only for sad approximation of original content; this might or might not matter.
If it matters, it's possible to convert a copy of the original field to MIME used only for display purposes, or scrape it out using DXL and storing separately - however this approach again means an issue of synchronization every time somebody changes the image in the original RT item.
2) computing URL as per OP code in the accepted self-answer is not possible in general as the constant 0.C4 in this example relates to the offset of the image in binary data of the RT item. Meaning any other design of rich text field, manually entered images, created by different version of Notes - all influence the offset.
3) the url can be computed correctly only by using C API that allows to investigate binary data in rich text item. This cannot be done from Java. IMO (without building JNI bridges etc)

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