Chimera Help

Program Info

This is Chimera 1.61, written by John Kilburg (john@cs.unlv.edu) and others (see the README file in the chimera distribution for more info). The HTML widget code was originally written at NCSA. Keep in mind that the HTML widget used by Chimera is a modified version and any problems are John's fault.

Click here to see the chimera home page. Click here to see the ISRI home page. ISRI is sponsering current development of chimera.

Click here to check out additional chimera goodies (tools, possible binaries, beta versions,...).

Bug Reports

The name of the mailing list is bug-chimera@cs.unlv.edu. If you want to join the list, send email to bug-chimera-request@cs.unlv.edu. Send bug reports to bug-chimera@cs.unlv.edu.

When you send a bug report please include the version of chimera that you are using, the type of machine/OS you are using, and one or more URLs that expose the bug.

Mouse Button Usage

If you click on an anchor with the first mouse button then the document will be loaded and displayed (if possible). If the second mouse button is used then Chimera will ask for a filename and save the document to the file. If the third mouse button is used then the anchor's URL is displayed.

Quit

Clicking on this button causes Chimera to stop execution. It is important that you use this button instead of, say, control-c. For instance, if you do not use the Quit button to exit Chimera any changes you make to the list of bookmarks will not be saved.

Open

This command tells Chimera to display a requester for a document URL. The cursor automatically warps to the text entry field so move movement is not required after the button is pressed. A click on the cancel button on the requester causes Chimera to discard the requester and resume operation as before. A click on the OK button causes Chimera to attempt to load the specified document. If the URL is invalid or the document is unavailable then an error message is displayed. If the document was successfully accessed then Chimera displays the document (in the case of HTML) or executes an external program to deal with the document.

You can also edit the URL display field which is located between the main document window and the document title display.

Home

When the home button is pressed the document that was first displayed is displayed. This is the same as pressing Back until the first document is visible.

Back

Clicking on this button causes Chimera to ``back up'' to the previous document. This button will be deactivated if only one document is available.

Source

Clicking on this button causes Chimera to display the HTML source of the currently displayed document.

Reload

Clicking on this button causes Chimera to reload the current document. This is useful for a when the original document has changed (you are currently working on a project, for example) and you need to refresh the document.

File

When this button is pressed a popup window appears which can be used to tell chimera to save or print the currently displayed document. There are three text fields: Filename, Printer, and Email. If you click on the Save button then the string in the Filename text field is used as the name of the file in which the document is saved. If you click on the Print button then the string in the Printer text field is used to determine which printer to use for printing. If you click on the Email button then the string in the Email text field is used to determine where to mail the document. There is also a menu button which can be used to select the output type. Note that when you print you must select the correct output type for your printer. If you try to print HTML on a postscript printer, for example, then nothing will happen. To print HTML source on a postscript printer you will first have to save the document as HTML and then use a utility (such as a2ps) to convert the HTML source to postscript which can then be printed on the printer.

Help

Clicking on this button causes Chimera to display the document you are reading now.

Bookmark

When you click on this button a list of bookmarks pops up. To view a document which has a bookmark just double click on the bookmark. Along the button of the bookmark list window is a row of four buttons: open, dismiss, add, and delete. The open button opens the currently highlighted bookmark. The dismiss button hides the bookmark list. The add button adds the title of the current document to the bookmark list (the URL is used if there is no title). The delete button deletes the currently highlighted bookmark.

Search

When the search button is pressed a requester appears which allows you to enter a string for Chimera to find. If the string is found then the document position is changed so that the string is viewable and the string is highlighted. Chimera only allows forward, case-insensitive searches. If the search reaches the end of the page, it will wrap to the top of the document.

Cancel

The cancel button can be used to stop the loading of the currently loading document. Note that cancel doesn't work while chimera tries to make a connection to a remote host. It only works once the transfer has started (most of the time).

Uniform Resource Locators (URLs)

URLs are used by Web clients to access a document. URLs describe the access method to be used to access the file, the Internet hostname where the document is located, an optional port number on the host, and the location of the document on the host. The format is:

access_method://hostname:optional_port/filename

Usually the port number is not used except when someone is running a server on a non-standard port. Do not specify the second colon if the port number is omitted.

This may sound complicated but here are a few examples to (hopefully) make things clearer:

Gopher server at UNLV - gopher://gopher.unlv.edu/

Web server at UNLV - http://www.unlv.edu/default.html

ftp server at UNLV - ftp://ftp.cs.unlv.edu/

Local file test.html - file:test.html

Hints

Chimera disconnects from a server as soon as it gets a document. While this is efficient in that it allows the user to browse data off line, it makes it difficult to continue access on busy servers. An example (a really good one, actually), is ftp access on wuarchive. Wuarchive is a very busy ftp server so it is sometimes difficult to get a connection. The problem is that if you get a directory listing and then select one of the items in the listing you may get a message like:

Could not load document ftp://wuarchive.wustl.edu/pub

This probably means that there are too many people on wuarchive. In this case just press ``Back'' and try again.

When you open a local file be sure to use the file access method. The reason for this is that if you give a partial URL the current document will be used to complete the URL. If you use file: then the current document is not used for context.

If for some reason there is a document that will not load correctly try doing a reload. If chimera was not configured correctly for some reason, it is possible for the cache to be incorrectly processed. After verifying the configuration, press Reload to make sure that the cache is processed correctly.

Keyboard Shortcuts

Space - scroll forward
b     - scroll backward
h     - home
u     - back
l     - reload
?     - help
q     - quit
d     - source
o     - open
w     - save
s     - search
p     - print
m     - bookmark

Environment variables

NOTE: The environment variables of the form CHIMERA* may go away at any time.

Chimera uses the following environment variables

CHIMERA_CACHE          See the explanation for the X resource cacheDir.

CHIMERA_CACHE_SIZE     See the explanation for the X resource cacheSize.

CHIMERA_DOC_TTL        See the explanation for the X resource docTTL.

CHIMERA_CACHE_OFF      See the explanation for the X resource cacheOff.

WWW_HOME               This is used to specify the first document to be
                       loaded.  X resource is homePage.

USER                   Used to determine the username of the user running
                       chimera.

PRINTER                This is used by chimera to determine the default
                       printer.  X resource is printerName.

http_proxy             This is used to specify the server to use for
                       proxied HTTP requests.  The format is the
                       same as an HTTP URL.  For example,
                       http://firewall.blah.edu/

gopher_proxy           This is used to specify the server to use for
                       proxied Gopher requests.  The format is the same
                       as an HTTP URL.  For example,
                       http://firewall.mumble.com/

ftp_proxy              This is used to specify the server to use for
                       proxied FTP requests.  The format is the same
                       as an HTTP URL.  For example,
                       http://foo.bar.ca/

wais_proxy             This is used to specify the server to use for
                       proxied WAIS requests.  The format is the same
                       as an HTTP URL.  For example,
                       http://barp.nv.us/

no_proxy               This is a comma separated list of domains that
                       should not be proxied.

X Resources

Here is a list of Chimera-specific X resources:

convertFiles           A colon separated list of files that describe the
                       converters.

homeURL                URL of the first document to load.

helpURL                URL of the help document.

path                   A colon separated list of directories to search
                       for viewer and conversion programs.

showURL                Boolean variable used to specify whether or not the
                       URL should be displayed on the screen.

showTitle              Boolean variable used to specify whether or not
                       the title should be displayed on the screen.

button1Box             A comma separated list of buttons to appear on the
                       first button row.  Possible button names are quit,
                       open, home, back, source, reload, save, help,
                       bookmark, print, search, and cancel.

button2Box             A list of buttons to appear on the second button
                       row.

printerName            Used to specify the name of the default printer.

cacheOff               The existence of this variable tells chimera
                       not to cache documents.

cacheDir               This is used to specify the directory where
                       cache files are stored.  Chimera will not create the
                       directory if it does not exist and caching will not
                       occur.

docTTL                 This specifies the time-to-live for cached documents.
                       If a document is accessed and the cache entry for that
                       document is more than docTTL seconds then the
                       document is reloaded from the source.  If zero then
                       documents are never reloaded (unless the reload
                       button is pressed).

cacheSize              This specifies the maximum size of the cache in bytes.
                       If the maximum size is exceeded then the least
                       recently accessed cache document is removed
                       to make room.  If zero then the cache is allowed to
                       grow to any size.

cleanUp                If True then chimera will remove the cache files
                       that it creates when it exits.

mimeTypeFiles          A colon separated list of files that map file
                       extensions to MIME content-types.

mailCapFiles           A colon separated list of MIME mailcap files to be used
                       by chimera.

bookmarkFile           The location of the bookmark file.

protocolFiles          A colon separated list of files that describe the
                       programs to be used for handling protocols.

statusUpdate           The number of times to update the download status
                       per read (or something).  Setting this to zero
                       gives the most updates while higher numbers give
                       fewer updates.

inPort                 The port number that chimera listens on for
                       incoming information from other programs.
                       By default, this is set to zero which disables
                       the feature.

Configuration Files

There are four different types of files that can be used to change Chimera's behavior: mailcap, MIME Types, convert, and protocol.

Mailcap

The mailcap file is used by MIME-capable applications to determine how to display certain file types. For example,

image/*; xv %s
audio/basic; playaudio %s

tells chimera to use the program 'xv' to display all images and to use the program playaudio (a wrapper for cat) to play basic audio files. You can specify multiple mailcap files by using the Chimera.mailCapFiles resource. For example,

Chimera.mailCapFiles:  ~/.mailcap:/local/infosys/lib/mailcap

The entries in the mailcap files at the head of the list take precedence over the following files.

Note that mailcap entries can have other fields delimited by semi-colons. Chimera currently ignores all but the first two fields.

MIME Types

The mime.types file is used to map filename extensions to MIME content types. For example,

text/plain            .txt .text
image/gif             .gif
image/jpeg            .jpg .jpeg

You can specify the location of mime.types files using the Chimera.mimeTypeFiles. For example,

Chimera.mimeTypeFiles: ~/.mime.types:/local/infosys/lib/mime.Types

Convert

Convert files are used to tell chimera how to convert certain types of files to other types. For example, convert entries are used to convert GIF to PNM files for display as inline images. The convert file is also used to decompress compressed files.

There are a several different types of convert entries. The first type has the form:

[cimg | gimg | mimg]   content-type      |command

The cimg, gimg, and mimg mean color image, grayscale image, and monochrome image, respectively. For example, you have a color display then chimera uses cimg entries to convert inline GIFs, JPEGs, and other image types to PNM files for display. The content-type field is one of the MIME data types and is used by chimera to determine which commands to use for different image types. The |command field is the command that is executed to convert the file. The '|' character ahead of the command is mandatory.

The second type of convert entry has the form:

[ftp | http | gopher | file ] content-type [http | '|']

These are used for general conversions and can be specified per protocol.

The third type of convert entry has the form:

command_name	*	[http | '|']

These entries are mostly used to do transfer and content decoding for HTTP transactions. The command_name is the name of the command specified in the MIME encoding fields.

If you specify 'http' for the third field in the above entries then chimera expects the output of the command to have an HTTP/MIME header at the beginning of input. This allows scripts to determine the best type to return and allows chimera to identify and display the data.

You can specify the location of several convert files with the Chimera.convertFiles resource variable. For example:

Chimera.convertFiles: ~/.chimera_convert:/local/infosys/lib/convert

In all cases, chimera saves the data in a temporary file and passes the name as an argument to the command. Chimera expects the command to output the converted data on stdout. See the convert file included with the chimera distribution for examples.

Protocol

The protocol files is used to specify external protocol programs for chimera. The format for protocol file entries is

protocol_name        command_name

The protocol name can be anything you want as long as it doesn't include white space. The command name is the full path name of the command. This is inconvenient but will work for now and will be changed in the future to utilize the PATH environment variable and/or the Chimera.path X resource.

The command should expect to receive, on stdin, an HTTP request which gives information about the location of the desired document. The program will know that chimera is sending data when a 'Content-length' field is included in the header and the length is greater than 0. For example, here is a typical header:

GET /something HTTP/1.0
User-Agent: Chimera/1.60
Accept: */*
URI: nntp:/comp.infosystems.announce
X-protocol: nntp
X-hostname:
X-port: 0
X-filename: /comp.infosystems.announce

The first line can be ignored (it isn't really needed) but it is kept around because that is what HTTP requires. Note that the fields can arrive in any order and some may be missing. A port value of 0 is used to indicate to the protocol that it is to use the default port. Also note that a field may be left blank in which case the program is expected to pick a "reasonable" default or return an error message.

Here is an example of forms data in a request:

POST /mumble HTTP/1.0
User-Agent: Chimera/56.34
Accept: */*
URI: pnews:/alt.bogus.whimpering
Content-type: x-www-form-urlencoded
Content-length: 46
X-protocol: pnews
X-hostname:
X-port: 0
X-filename: /alt.bogus.whimpering

field1=mumble&field2=blah&field3=barp&field4=

Once the program has collected its data it should output the data with an HTTP header prepended. For example,

HTTP/1.0 999 Ooops
Content-type: text/plain
Content-length: 42

You specified a bogus newsgroup.  Go away.

There must be a blank line between the header and the data. You can use the 'Location' or 'URI' fields to specify alternate URLs (or whatever they're called now) for Chimera to load. At the very minimum you should include the Content-type and Content-length fields.

You can also use the 'Pragma' field to provide hints about how to handle the document. Currently, the only supported value is 'nocache'. For example,

Pragma: nocache

If 'nocache' is present then chimera will not cache the document which is useful for constantly changing information.

Slow Network Connections

If you have a slow network connection then you may want to enable delayed inline image loads. Set the X resource Chimera*delayImageLoads to True so that inline images are not downloaded.