We're writing a parser for ACORD AL3. Read AL3 coming in, write AL3 going out. Nice and simple.
As of right now, it is 99% solid. The only thing that's driving me nuts is the use of "?"s in the ACORD AL3 standard. It appears that they are used as placeholders for fields that do not have values in the message. HOWEVER, that's not the only rule for it, because if it was, the AL3 I'm currently generating would look that the sample files I'm trying to have it match.
So if anyone here knows anything about the rules around AL3 "?"s, that would be great. I've been pouring over the Data Dictionary and the other documentation from ACORD, and I'm seeing nothing to indicate which fields get it, and which ones don't.
Also, if the "?"s are not required for AL3 processing to begin with, that would also be great to know, because then I could just stop worrying about the whole thing.
In the ACORD AL3 standard, from what I recall, if you use a "?" in one of the fields, this tells the receiving system to not overwrite (with blanks) the target field in the user's management system.
There may be individual elements in a group that are valid, but the sender
cannot send them for some reason. The solution is to fill that data element with questions marks (?????) The receiving system will recognize this and not update that field on their system.
In ACORD Al3 "?" means there is not any data in that specific element but that element is much important to maintain the hierarchy. But there is one thing, Coverage groups and Transaction groups will not contains any question mark. that does not means these are not important even these are very much important in Al3 files. But that above mentioned description applies for data group.
Secondly number of question marks in element describe its length.
If anyone need more details related to al3 data, don't hesitate to ask.
Related
Can anyone actually explain, in layman's terms, what is a real-world use case for the set operation's options?
While I fully understand what set with merge does, as well as merge beeing a boolean and mergeFields being an array of fieldPaths, I cannot think of cases in which mergeFields might be of any use.
I also understand the fact that mergeFields basically acts like a mask for the object passed to the set operation, but I still cannot think of how is it so useful that it actually got implemented within the SDK.
Can someone shed some light?
After looking through the documentation, there seem to be two reasons why you might want to use one vs the other:
mergeFieldPaths/mergeFields trigger an error when passing in field values that don't currently exist on the document while merge will add in those fields if they don't exist. The error is good for safety purposes if you're concerned about typos/writing to incorrect field paths.
This one is just a guess, but the documentation indicates mergeFieldPaths/mergeFields ignores AND leaves fields untouched while merge ONLY leaves other fields untouched. It's possible there's some performance advantage to using mergeFieldPaths/mergeFields esp for documents with a ton of fields. The difference might be direct access vs still needing to look at unspecified fields to identify the matches in some way.
SetOptions Reference
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Last week, I had to create a little GUI for homework.
None of my school mates did it. They have stolen my one from where we had to upload it and then they uploaded it again as theirs. When I told my teacher it was all my work he did not believe me.
So I thought of putting a useless method or something inside with a proof that I coded it. I thought of encryption. My best idea up till now:
String key = ("ZGV2ZWxvcGVkIGJ5IFdhckdvZE5U"); //My proof in base64
Can you think of some other better ways?
I had the same problem as you a long time ago. We had Windows 2000 machines and uploaded files to a Novel network folder that everyone could see. I used several tricks to beat even the best thieves: whitespace watermarking; metadata watermarking; unusual characters; trusted timestamping; modus operandi. Here's them in order.
Whitespace watermarking:
This is my original contribution to watermarking. I needed an invisible watermark that worked in text files. The trick I came up with was to put in a specific pattern of whitespace between programming statements (or paragraphs). The file looked the same to them: some programming statements and line breaks. Selecting the text carefully would show the whitespace. Each empty line would contain a certain number of spaces that's obviously not random or accidental. (eg 17) In practice, this method did the work for me because they couldn't figure out what I was embedding in the documents.
Metadata watermarking
This is where you change the file's metadata to contain information. You can embed your name, a hash, etc. in unseen parts of a file, especially EXE's. In NT days, Alternate Data Streams were popular.
Unusual characters
I'll throw this one in just for kicks. An old IRC impersonation trick was to make a name with letters that look similar to another person's name. You can use this in watermarking. The Character Map in Windows will give you many unusual characters that look similar to, but aren't, a letter or number you might use in your source code. These showing up in a specific spot in someone else's work can't be accidental.
Trusted Timestamping
In a nutshell, you send a file (or its hash) to a third party who then appends a timestamp to it and signs it with a private key. Anyone wanting proof of when you created a document can go to the trusted third party, often a website, to verify your proof of creation time. These have been used in court cases for intellectual property disputes so they are a very strong form of evidence. They're the standard way to accomplish the proof you're seeking. (I included the others first b/c they're easy, they're more fun and will probably work.)
This Wikipedia article might help your instructor understand your evidence and the external links section has many providers, including free ones. I'd run test files through free ones for a few days before using them for something important.
Modus operandi
So, you did something and you now have proof right? No, the students can still say you stole the idea from them or some other nonsense. My fix for this was to, in private, establish one or more of my methods with my instructor. I tell the instructor to look for the whitespace, look for certain symbols, etc. but to never tell the others what the watermark was. If the instructor will agree to keep your simple techniques secret, they will probably continue to work fine. If not, there's always trusted timestamping. ;)
If your classmates stole your code from the upload site, I would encrypt your homework and email the key to the teacher. You can do this with PGP if you want to be complicated, or something as simple as a Zip file with a password.
EDIT:
PGP would allow you to encrypt/sign without revealing your key, but you can't beat the shear simplicity of a Zip file with a password, so just pick a new key every homework assignment. Beauty in simplicity :)
If you are giving source code to the teacher, then simply add a serialVersionUID to one of your class files that is an encrypted version of your name. You can decrypt it to the teacher yourself.
That does not mean anything to the others, just for you. You can say it's a generated code, if they're stealing it, probably won't bother to modify it at all.
If you want to do it in a stylish way, you could use this trick, if you find the random seed that produces your name. :) That would be your number then, and wherever it appears that would prove that it was you who made that code.
This happened with a pair of my students who lived in the same apartment. One stole the source code from a disk left in a desk drawer.
The thief slightly modified the stolen source, so that it wouldn't be obvious. I noticed the similarity of the code anyway, and examined the source in an editor. Some of the lines had extra spaces at the ends. Each student's source had the same number of extra spaces.
You could exploit this to encode information without making it visible. You could encode your initials or your student ID at the ends of some lines, with spaces.
A thief will likely make cosmetic changes to the visible code, but may miss the non-visible characters.
EDIT:
Thinking about this a little more, you could use spaces and tabs as Morse-code dits and dahs, and put your name at the end of multiple lines. A thief could remove, reorder or retype some lines without destroying your identification.
EDIT 2:
"Whitespace steganography" is the term for concealing messages in whitespace. Googling it reveals this open-source implementation dating back to the '90s, using Huffman encoding instead of Morse code.
It seems like an IT administration problem to me. Each student should have there own upload area which cannot accessed by other students.
The teacher would be a higher level up, being able to access each student upload folder. If this is not possible go with #exabrial answer as that is the simpliest solution.
The best thing you can do is to just zip the source code with a password and e-mail the password to the teacher.
Problem solved.
Use a distributed (=standalone) version control system, like git. Might be useful too.
A version history with your name, and dates might be sufficiently convincing.
What was stolen ?
The source ? You can put random Strings in it (but it can be changed). You can also try to add a special behavior know only from you (a special keypress will change a color row), you can then ask to the teacher "the others know this special combo ?". Best way will be to crash the program if a empty useless file is not present in the archive after 5 minutes of activity, your school mates will be too lazy to wait this ammount of time.
The binary ? Just comparing the checksum of each .class will be enough (your school mates are too lazy to rewrite the class files)
Just post your solution at the last minute. This won't give time to anyone to copy it.
And send a feedback to the administrator to disallow students to see other students assignments.
If you upload the file in a .zip with password encryption, anyone can just crack the password by downloading the .zip file and have their cpu run a million queries at it if they are that big of a cheat thief. Unfortunately, some are and it's easy to do.
Your source can be viewed on the shared server by the other students. The teacher should really be giving you your own password encrypted directory to upload to. This could be done easily just by adding subdomains. But perhaps the teacher might allow you to upload the files to your own server for him to access them there.
It's also possible to obfuscate the script so that it has a document.write('This page was written by xxxxx'), forcing anyone who copies your work to not be able to remove the credit unless they first decrypt it. But the real answer is that your school needs to give each of its students their own password protected directories.
In my case, my teachers came with a better approach. The questions they provided has something to do with our registration number.
Ex:
Input to a function/theory is our Registration number, which is
different for each student
So, answers or the approach to the solution are relatively different from each student.This make the necessarily of all students has to do their homework on their own, or at-least get to know how to hack the approach with their own registration[it may be harder than learning the lession ;)].
Hope your lecturer will read this thread before his next tutorial :D
I'm comming from the java world, and i'd like to know if there's anything that can help me understand the properties of abap development objects.... something like reflection.
Knowing that everything that goes on in ABAP is persisted somewhere inside a database, i'd like to know how would i go about finding out HOW and WHERE an object is saved.
For instance, i'd like to know if there are any functions that enumerate the fields of a structure, or enumerate the properties of an object, or if there's no such thing (but the properties still exist obviously), then what table would be holding those (so that i can create my own functions, or classes)
Also any other discoverability tricks that you know are good... I know this question is a little generic, but since i'm new to abap, i don't really know what to ask :P
Thx, you guys rule.
If you're looking for something like reflection, take a look at RTTI. This cvers the runtime structure of most of the stuff you'll come across. If you want to find out what's going on underneath the surface of the cevelopment tools, just turn on the SQL trace (ST05), open the object in question in an editor and check what tables are accessed...
It is hard to answer your question, maybe it would be easier, if you split it up in multiple questions with some specific task you want.
Some topics I remember (please verify it, I can't check it in the moment if I remember correct):
DDIC-objects are stored in tables with DD*.
Tables (and there properties) are stored in dd02l, dd02t includes the texts. dd03l contains the fields. dd04tl contains the texts of data element.
But it will not help you, if you add something to this tables. The database in background will not get the definitions.
If you want to create some dynmaic magic you may take a look to the field-symbols and assign-command.
I am tasked with writing a program that, given a search term and the HTML source of a page representing search results of some unknown search engine (it can really be anything, a blog, a shop, Google, eBay, ...), needs to build a data structure of the results containing "what's in the results": a title for earch result, the "details" link, the position within the results etc. It is not known whether the results page contains any of the data at all, and whether there are any search results. The goal is to feed the data structure into another program that extracts meaning.
What I am looking for is not BeautifulSoup or a RegExp but rather some clever ideas or algorithms on how to interpret the HTML source. What do I do to find out what part of the page constitutes a single result item? How do I filter the markup noise to extract the important bits? What would you do? Pointers to fields of research covering what I try to to are aly greatly appreciated.
Thanks, Simon
I doubt that there exist a silver-bullet algorithm that without any training will just work on any arbitrary search query output.
However, this task can be solved and is actually solved in many applications, but with different approach. First you have to define general structure of single search result item based on what you actually going to do with it (it could be name, date, link, description snippet, etc.), and then write number of html parsers that will extract necessary necessary fields from search result output of particular web sites.
I know it is not super sexy solution, but it probably the only one that works. And it is not rocket science. Writing parsers is actually extremly simple, you can make dozen per day. If you will look into html source of search result, you will notice that output results are typically very structured and marked with specific div sections or class atributes, so it is very easy to find it in the document. You dont have even use any complicated HTML parsing library for that, something grep-like will be enough.
For example, on this particular page your question starts with <div class="post-text"> and ends with </div>. Everything in between is actually a post text with some HTML formatting that you may want to remove along with extra spaces and "\n". And this <div class="post-text"> appears on the page only once.
Once you go at large scale with your retrieval applicaiton, you will find out that there is not that big variety of different search engines on different sites, and you will be able to re-use already created parsers for sties using similar search engines.
The only thing you have to remember is built-in self-testing. Sites tend to upgrade and change design from time to time. If your application is going to live for some time, you will need to include into your parsers some logic that will check validity of their results and notify you every time search output has changed and is not compatible anymore with your parser. Then you will have to modify particular parser or write new one.
Hope this helps.
I'm building a form and I wonder if there is a significant advantage in showing values in a more human readable format; e.g:
index.php?user=ted&location=newyork
Rather than:
index.php?user=23423&location=34645
On the one hand, having the query string a little more readable allows the user and search engines to better understand where they are, but this also creates a little more work on the server side, as I'll have to track down the associated rows through something other than their unique id.
For example, first find what the id of 'newyork' is before being able to work on other rows that require the location_id. I always prefer to give the db as little work as possible.
Edit: decided to go with readability. I figure I can always use the mysql query cache to speed things up if necessary.
Use human readable values when you can. Just be sure to sanitise the input.
Edit: Yes, this can and should still be done for SEO purposes (if its worth it to you) if you have lots of choices. Even if the user has lots of choices, you should know what they are (or what the limits are) so that you can properly sanitise the input. For instance, if they are choosing states, you can know all 50. If they are just making up their own text, make sure on your end that its only text.
A good rule of thumb is to store data as id's and display it as human readable text etc.
Depends on your goals.
If you are talking about something like a blog where you want everyone to see everthing (and find it easily), then the human/search engine readable format is a no brainer.
If these pages are locked behind a login then it doesn't much matter. You can do what is easier on the database.
For most internet apps, I'd err to the side of readability since that will help with search engines as well.
You shouldn't worry about the efficiency for any typically sized application on any reasonable database engine. Write your app for users, not for query optimizers. QO's can more easily take care of themselves. Deal with optimization in the unlikely event you start seeing a problem.
I am going to come from a different direction. In my opinion a URL should be readable if want the user to be able to use the URL to change their parameters by editing the URL instead of using the UI. An example would be https://www.coolreportingapp.com/accountReport.jsp?account=ABC&month=200911 . In this example, the user can "easily" change the account or month they looking at without messing with the UI. This of course means you need to validate the URL params each and every time, which you should do anyway. If you don't want the user to alter the URL params, you need to obfuscate and hash values and use the hash to verify they haven't.
Seriously, IMHO, in your example, none is more readable than the other. Do normal users know that "&" is a separator from "variables" in "user=ted&location=newyork&"? Do they need to know that exists something like a variable? Having this in mind, what's the difference in showing numbers or words?
If you really want readable urls you should build SEO Friendly urls (human readable). Remember that even a "dashes vs underscores" simple question matters in the end.