Generating PDFs - Approach to store the generating code - ruby

I'm currently writing an rails application that generates some PDFs. The generated documents are things like proposals, invoices, order confirmations etc.
My intention is to provide 2 default layouts and to allow the user to request a custom layout. The user will never even see the generator code, this is all handled by trusted persons -> security is no concern at all.
My requirements:
Easy to change / add new generators (for developers, users never see those generators)
No redeployment
Works well with any number of generators
The way I see it, implementing those generators as regular classes in .rb files in the source code falls flat (redeployment required, file clutter with enough of them).
I'm currently thinking about the following and would like some input into the viability / better ways to do it:
The generator code is stored in the database and whenever a document is to be printed, the code is evaled in a scope where all the relevant variables are already set (document (-> line items | customer ..), pdf, user etc.) and the generator code just uses them.
My questions is basically: Is this the way to do it and if that's the case, are there some things I should be aware of?

Related

How do I access h2o xgb model input features after saving a model to disk and reloading it?

I'm using h2o's xgboost implementation in Python. I've saved a model to disk and I'm trying to load it later on for analysis and predicting. I'm trying to access the input features list or, even better, the feature list used by the model which does not include the features it decided not to use. The way people advise doing this is to use varimp function to get the variable importance and while this does remove features that aren't used in the model this actually gives you the variable importance of intermediate features created by OHE the categorical features, not the original categorical feature names.
I've searched for how to do this and so far I've found the following but no concrete way to do this:
Someone asking something very similar to this and being told the feature has been requested in Jira
Said Jira ticket which has been marked resolved but I believe says this was implemented but not customer visible.
A similar ticket requesting this feature (original categorical feature importance) for variable importance heatmaps but it is still open.
Someone else who found an unofficial way to access the columns with model._model_json['output']['names'] but that doesn't give the features that weren't used by the model and they are told to use a different method that doesn't work if you have saved the model to disk and reloaded it (which I am doing).
The only option I see is to just use the varimp features, split on period character to break the OHE feature names, select the first part of all the splits, and then run a set over everything to get the unique column names. But I'm hoping there's a better way to do this.

Applying different parsefilters to each domain in the same topology

I am trying to crawl different websites (e-commerce websites) and extract specific information from the pages of each website (i.e. product price, quantity, date of publication, etc.).
My question is: how to configure the parsing since each website has a different HTML layout which means I need different Xpaths for the same item depending on the website? Can we add multiple parser bolts in the topology for each website? If yes, how can we assign different parsefilters.json files to each parser bolt?
You need #586. At the moment there is no way to do it but to put all your XPATH expressions regardless of the site you want to use them on in the parsefilters.json.
You can't assign different parsefilters.json to the various instances of a bolt.
UPDATE however you could have multiple XpathFilters sections within the parseFilters.json. Each could cover a specific source, however, there is currently no way of constraining which source a parse filter gets applied to. You could extend XPathFilter so that it takes some extra config e.g. regular expression a URL must match in order to be applied. That would work quite nicely I think.
I've recently added JsoupFilters which will be in the next release. These should be useful for your use case but that still doesn't solve the issue that you need an implementation of the filter that organizes the resources per host. It shouldn't be too hard to implement taking the URL filter one as a example and would also make a very nice contribution to the project.

Getting most relevant content from page

I need to create a universal web scraper to parse articles on the different websites. Of course, I know about XPath, but I want to try to make it universal for any website despite the HTML markup of a page.
I need to determine whether there is an article on the page and if it is - parse a text of title, body and tags (if exists).
Frankly speaking, my knowledge in DS is not very huge, but I assume this task (determine whether it is article, and parsing only needed parts) is possible to solve.
What tools should I use? Any help?
Actually, for the second task, I need to implement something similar that google chrome mobile does. When page is not optimised for mobile, then propose to show the page in adaptive mode (just title, and main content).
If you are using Python, some libraries to look at are:
scrapy, which scrapes data and can extract some of the results) and,
BeautifulSoup, which is more geared towards the extraction part itself.
It is possible to request a version of a website (e.g. for Chrome, Safari, Mobile, old-school systems) by creating a custom header for your scraper.
HAve a look at the relevant documentation, and you can get an idea of how to use headers in scrapy here.
I do not know of any more specialised tools. Your tasks are more analytical and are typically not performed with the use of models for estimating e.g. what content is where on a webpage. This might be an intersting research direction though; to see if you can create a model that generalises across many websites to extract the desired content.
That leads me on to my last point, which is to say that creating a single scraper that works for any website *containing your artile type) is not usually possible. People create websites differently, however they see fit, which means they also change them. This usually leads to a good scraper requiring constant updates as time (and developers) moves on.
EDIT:
Then if you have lots of labelled examples, it might be possible to train a model. The challenge might be the look-back range of the model. For example, a typical LSTM model is given a parameter that tells it how far to look back into the past. It is stored within its memory internally. In your case, you might be looking for a start and end HTML tag of an article, to then extract just that part. These tahs could be thousands of words apart. Something a standard LSTM might not be fit to retain and use.
If you could pose your problem a little differently, then there are other approaches that might be plausible. E.g., you could make it a "question-answer" problem, by saying: I have this HTML, where is the article content? If that sounds ok for your use-case, have a look here for some model based approaches.

Report Design Templates

We are using DevExpress XtraReports 2009v3.3 and although I can achieve what I want through various formatting objects in code, there must be a (better/less painless/maintainable/visual) way of achieving what I require...
I need to produce a report, designed to end-user 'look & feel'. We have many companies which use our software and they all require different design schema's/templates for their reports. For example - a single report, depending on who logs on (we know what company they belong to) apply the template the report should use.
As an example, some of the requirements (per end-user/company) include:
their own logo (positioned in the correct place),
Margins being of specific size
their own fonts (or font choice)
alternating colours schemes
Specific rows / columns being particular colours (both permanently and based on value)
Formatting of values, for example a european user would get euro, a uk user gets pounds on certain columns/cells/rows.
I know there is an End-User Report Designer, however this isn't what we require - I must create the schema/template design for a report then apply it at runtime.
Also using save/load layout for multiple repx files isn't the best solution as a change to the report would cause a lot of extra work as you would have to update each repx template file.
It is possible to create different reports and save it to the repx format via XtraReport.SaveLayout method and use these repx files as template.
Similar but different question
I asked dev express and they basically said there isn't any 'layout abstraction' that would do what I require.

How do you manage the String Translation Process?

I am working on a Software Project that needs to be translated into 30 languages. This means that changing any string incurs into a relatively high cost. Additionally, translation does not happen overnight, because the translation package needs to be worked by different translators, so this might take a while.
Adding new features is cumbersome somehow. We can think up all the Strings that will be needed before we actually code the UI, but sometimes still we need to add new strings because of bug fixes or because of an oversight.
So the question is, how do you manage all this process? Any tips in how to ease the impact of translation in the software project? How to rule the strings, instead of having the strings rule you?
EDIT: We are using Java and all Strings are internationalized using Resource Bundles, so the problem is not the internationalization per-se, but the management of the strings.
I'm not sure the platform you're internationalizing in. I've written an answer before on the best way to il8n an application. See What do I need to know to globalize an asp.net application?
That said - managing the translations themselves is hard. The problem is that you'll be using the same piece of text across multiple pages. Your framework may not, however, support only having that piece of text in one file (resource files in asp.net, for instance, encourage you to have one resource file per language).
The way that we found to work with things was to have a central database repository of translations. We created a small .net application to import translations from resource files into that database and to export translations from that database to resource files. There is, thus, an additional step in the build process to build the resource files.
The other issue you're going to have is passing translations to your translation vendor and back. There are a couple ways for this - see if your translation vendor is willing to accept XML files and return properly formatted XML files. This is, really, one of the best ways, since it allows you to automate your import and export of translation files. Another alternative, if your vendor allows it, is to create a website to allow them to edit the translations.
In the end, your answer for translations will be the same for any other process that requires repetition and manual work. Automate, automate, automate. Automate every single thing that you can. Copy and paste is not your friend in this scenario.
Pootle is an webapp that allows to manage translation process over the web.
There are a number of major issues that need to be considered when internationalizing an application.
Not all strings are created equally. Depending upon the language, the length of a sentence can change significantly. In some languages, it can be half as long and in others it can be triple the length. Make sure to design your GUI widgets with enough space to handle strings that are larger than your English strings.
Translators are typically not programmers. Do not expect the translators to be able to read and maintain the correct file formats for resource files. You should setup a mechanism where you can transform the translated data round trip to your resource files from something like an spreadsheet. One possibility is to use XSL filters with Open Office, so that you can save to Resource files directly in a spreadsheet application. Also, translators or translation service companies may already have their own databases, so it is good to ask about what they use and write some tools to automate.
You will need to append data to strings - don't pretend that you will never have to or you will always be able to put the string at the end. Make sure that you have a string formatter setup for replacing placeholders in strings. Furthermore, make sure to document what are typical values that will be replaced for the translators. Remember, the order of the placeholders may change in different languages.
Name your i8n string variables something that reflects their meaning. Do you really want to be looking up numbers in a resource file to find out what is the contents of a given string. Developers depend on being able to read the string output in code for efficiency a lot more than they often realize.
Don't be afraid of code-generation. In my current project, I have written a small Java program that is called by ant that parses all of the keys of the default language (master) resource file and then maps the key to a constant defined in my localization class. See below. The lines in between the //---- comments is auto-generated. I run the generator every time I add a string.
public final class l7d {
...normal junk
/**
* Reference to the localized strings resource bundle.
*/
public static final ResourceBundle l7dBundle =
ResourceBundle.getBundle(BUNDLE_PATH);
//---- start l7d fields ----\
public static final String ERROR_AuthenticationException;
public static final String ERROR_cannot_find_algorithm;
public static final String ERROR_invalid_context;
...many more
//---- end l7d fields ----\
static {
//---- start setting l7d fields ----\
ERROR_AuthenticationException = l7dBundle.getString("ERROR_AuthenticationException");
ERROR_cannot_find_algorithm = l7dBundle.getString("ERROR_cannot_find_algorithm");
ERROR_invalid_context = l7dBundle.getString("ERROR_invalid_context");
...many more
//---- end setting l7d fields ----\
}
The approach above offers a few benefits.
Since your string key is now defined as a field, your IDE should support code completion for it. This will save you a lot of type. It get's really frustrating looking up every key name and fixing typos every time you want to print a string.
Someone please correct me if I am wrong. By loading all of the strings into memory at static instantiation (as in the example) will result in a quicker load time at the cost of additional memory usage. I have found the additional amount of memory used is negligible and worth the trade off.
The localised projects I've worked on had 'string freeze' dates. After this time, the only way strings were allowed to be changed was with permission from a very senior member of the project management team.
It isn't exactly a perfect solution, but it did enable us to put defects regarding strings on hold until the next release with a valid reason. Once the string freeze has occured you also have a valid reason to deny adding brand new features to the project on 'spur of the moment' decisions. And having the permission come from high up meant that middle managers would have no power to change specs on your :)
If available, use a database for this. Each string gets an id, and there is either a table for each language, or one table for all with the language in a column (depending on how the site is accessed the performance dictates which is better). This allows updates from translators without trying to manage code files and version control details. Further, it's almost trivial to run reports on what isn't translated, and keep track of what was an autotranslation (engine) vs a real human translation.
If no database, then I stick each language in a separate file so version control issues are reduced. But the structure is basically the same - each string has an id.
-Adam
Not only did we use a database instead of the vaunted resource files (I have never understood why people use something like that which is a pain to manage, when we have such good tools for dealing with databases), but we also avoided the need to tag things in the application (forgetting to tag controls with numbers in VB6 Forms was always a problem) by using reflection to identify the controls for translation. Then we use an XML file which translates the controls to the phrase IDs from the dictionary database.
Although the mapping file had to be managed, it could still be managed independent of the build process, and the translation of the application was actually possible by end-users who had rights in the database.
The solution we came up to so far is having a small application in Excel that reads all the property files, and then shows a matrix with all the translations (languages as headers, keys as rows). It is quite evident what is missing then. This is send to the translators. When it comes back, then the sheet can be processed to generate the same property bundles back again. So far it has eased the pain somewhat, but I wonder what else is around.
This google book - resource file management gives some good tips
You can use Resource File Management software to keep track of strings that have changed and control the workflow to get them translated - otherwise you end up in a mess of freezes and overbearing version control
Some tools that do this sort of thing - no connection an I haven't actually used them, just researching
http://www.sisulizer.com/
http://www.translationzone.com/en/products/
I put in a makefile target that finds all the .properties files and puts them in a zip file to send off to the translators. I offered to send them just diffs, but for some reason they want the whole bundle of files each time. I think they have their own system for tracking just differences, because they charge us based on how many strings have changed from one time to the next. When I get their delivery back, I manually diff all their files with the previous delivery to see if anything unexpected has changed - one time all the PT_BR (Brazillian Portuguese) strings changed, and it turns out they'd used a PT_PT (Portuguese Portuguese) translator for that batch in spite of the order for PT_BR.
In Java, internationalization is accomplished by moving the strings to resource bundles ... the translation process is still long and arduous, but at least it's separated from the process of producing the software, releasing service packs etc. One thing that helps is to have a CI system that repackages everything any time changes are made. We can have a new version tested and out in a matter of minutes whether it's a code change, new language pack or both.
For starters, I'd use default strings in case a translation is missing. For example, the English or Spanish value.
Secondly, you might want to consider a web app or something similar for your translators to use. This requires some resources upfront, but at least you won't need to send files around and it will be obvious for the translators which strings are new, etc.

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