JavaScript log parser project: Bad idea?

There are numerous log files that I have to review daily for my job. Several good parsers already exist for these log files but I have yet to find exactly what I want. Well, who could make something more tailored to you than you, right?

The reason I am using JavaScript (other than the fact that I already know it) is because it's portable (no need to install anything) but at the same time cross-platform accessible. Before I invest too much time in this, is this a terrible method of accomplishing my goal?

1. The input will be entered into a text file, delimited by [x] and the values will be put into an array to make accessing these values faster than pulling the static content.
2. Any special formatting (numbers, dates, etc) will be dealt with before putting the value in the array to prevent a function from repeating this step every time it is used.
3. These logs may contain 100k+ lines which w开发者_开发问答ill be a lot for the browser to handle. However, each line doesn't contain a ton of information.
4. I have written some of it already, but with even 10,000 lines it's starting to run slow and I don't know if it's because I wasn't efficient enough or if this just cannot be effectively done. I'm thinking this is because all the data is in one giant table. I'd probably be better off paginating it, but that is less than desirable.

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Question 1: Is there anything I failed to mention that I should consider?

Question 2: Would you recommend a better alternative?

Question 3: (A bit off topic, so feel free to ignore). Instead of copy/pasting the input, I would like to 'open' the log file but as far as I know JavaScript cannot do this (for security reasons). Can this be accomplished with a input="file" without actually having a server to upload to? I don't know how SSJS works, but it appears that I underestimated the limitations of JavaScript.

I understand this is a bit vague, but I'm trying to keep you all from having to read a book to answer my question. Let me know if I should include additional details. Thanks!

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I think JavaScript is an "ok" choice for this. Using a scripting language to parse log files for personal use is a perfectly sane decision.

However, I would NOT use a browser for this. Web browsers place limitations on how long a bit of javascript can run, or on how many instructions it is allowed to run, or both. If you exceed these limits, you'll get something like this:

Since you'll be working with a large amount of data, I suspect you're going to hit this sooner or later. This can be avoided by clever use of setTimeout, or potentially with web workers, but that will add complexity to your project. This is probably not what you want.

Be aware that JavaScript can run outside of browsers as well. For instance, Windows comes with the Windows Script Host. This will let you run JavaScript from the command prompt, without needing a browser. You won't get the "Script too long" error. As an added bonus, you will have full access to the file system, and the ability to pass command-line arguments to your code.

Good luck and happy coding!

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To answer your top question in bold: No, it is not a terrible idea.

If JS is the only language you know, you want to avoid setting up any dependencies, and you want to stay platform-independent... JavaScript seems like a good fit for your particular case.

As a more general rule, I would never use JS as a language to write a desktop app. Especially not for doing a task like log parsing. There are many other languages which are much better suited to this type of problem, like Python, Scala, VB, etc. I mention Python and Scala because of their script-like behaviour and minimal setup requirements. Python also has very similar syntax to JS so it might be easier to pick up then other languages. VB (or any .NET language) would work too if you have a Visual Studio license because of it's easy to use GUI builder if that suits your needs better.

My suggested approach: use an existing framework. There are hundreds, if not thousands of log parsers out there which handle all sorts of use-cases and different formats of logs that you should be able to find something close to what you need. It may just take a little more effort than Google'ing "Log Parsers" to find one that works. If you can't find one that suits your exact needs and you are willing to spend time making your own, you should use that time instead to contribute to one of the existing ones which are open source. Extending an existing code base should always be considered before trying to re-invent the wheel for the 10th gillion time.

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Given your invariants "javascript, cross-platform, browser ui, as fast as possible" I would consider this approach:

1. Use command line scripts (windows: JScript; linux: ?) to parse log files and store 'clean'/relevant data in a SQLite Database (fall back: any decent scripting language can do this, the ready made/specialized tools may be used too)
2. Use the SQLite Manager addon to do your data mining with SQL
3. If (2) gets clumsy - use the SQLite Manager code base to 'make something more tailored'

Considering your comment:

For Windows-only work you can use the VS Express edition to write an app in C#, VB.NET, C++/CLI, F#, or even (kind of) Javascript (Silverlight). If you want to stick to 'classic' Javascript and a browser, write a .HTA application (full access to the local machine) and use ADO data(base) access and try to get the (old) DataGrid/Flexgrid controls (they may be installed already; search the registry).