Blue Crab is a program that you use to copy the contents of a website to your computer, whole or in part.
You can use it for faster offline browsing and searching. Or it can be used as a labor saving device at times when you need to download an archive of images, PDF's, or any other media type.
With Blue Crab you can download all the content including HTML, PDF, graphics, video, file archives, etc., or use powerful selective filtering to restrict downloads to specific kinds of files. For example, you can choose to save only the JPEG images Blue Crab finds, or just the PDFs.
Starting with a single URL Blue Crab begins traversing the site by following the links on the HTML pages it finds. Blue Crab does not stray off the domain of the starting URL; in other words it won't download the whole web! Moreover, you can restrict Blue Crab to a subset of the given website.
Blue Crab is gentle on the server. It processes only one URL at a time and may be configured to grab resources at preset time intervals.
Here are some key features of "Blue Crab":
· Unique URL extraction algorithms yield very complete downloads compared to other products of this type.
· You can download websites either for offline browsing, via re-linking of URLs, or to create virtual copies of them on your hard drive, i.e. backup a website as-is.
· Supports both HTTP, HTTPS protocols as well as server realms. Detailed Grabber window shows server HTTP header response fields.
· Optionally display web pages as they are crawled using either your own web browser or Blue Crabs own web window.
· You can restrict a crawl to just the initial domain, or allow the program to 'stray' into offsite URLs.
· Blue Crab can remap 'dynamic' URLs which contain path and search arguments so that resulting disk files are navigable offline.
· Image URLs into JPEG files (or any other graphic file type supported by Quicktime) to create complete pictures of web pages not possible simply by taking a single screenshot yourself.
· Blue Crab provides its URL imaging ability as a service menu item available from other applications.
· URLs can be imaged into files, or onto the clipboard.
· Built-in directory search displays found files as a hierarchical list, with double-clickable entries.
· A 'batch window' enables you to download your own list of files. Simply drag and drop URLs into the batch window, or import them from an HTML file , or text file.
· Grabbing in 'images-only' mode just downloads image files, optionally 'flattening' the results (i.e. putting all images into one folder.)
Reusable configuration settings control what is grabbed, saved or crawled:
· Filter by size, date, file type or even content
· Filter by filename, extension or path
· Bookmarks window for storing frequently crawled websites.
· Supports form submissions to enable you to begin a crawl from a login page.
· Supports cookies for more accurate downloads.
· Generate site maps that consist of a hierarchical display of URLs. Such maps can be optionally filtered by extension.
· Find email addresses.
· Customizable user-agent (spoofing) enables you to download websites which are platform specific.
· Optionally receive email notifications of Blue Crab's progress during a lengthy crawl.
· Dock badging provides visual feedback or progress when the program is in the background.
