1. `Reading a file`_
2. `Writing/Uploading a File`_
3. `Creating a New Directory`_
- 4. `Get Information About A File Or Directory (as JSON)`_
- 5. `Attaching an existing File or Directory by its read- or write-cap`_
- 6. `Adding multiple files or directories to a parent directory at once`_
- 7. `Deleting a File or Directory`_
+ 4. `Getting Information About A File Or Directory (as JSON)`_
+ 5. `Attaching an Existing File or Directory by its read- or write-cap`_
+ 6. `Adding Multiple Files or Directories to a Parent Directory at Once`_
+ 7. `Unlinking a File or Directory`_
6. `Browser Operations: Human-Oriented Interfaces`_
1. `Viewing A Directory (as HTML)`_
2. `Viewing/Downloading a File`_
- 3. `Get Information About A File Or Directory (as HTML)`_
+ 3. `Getting Information About A File Or Directory (as HTML)`_
4. `Creating a Directory`_
5. `Uploading a File`_
6. `Attaching An Existing File Or Directory (by URI)`_
- 7. `Deleting A Child`_
+ 7. `Unlinking A Child`_
8. `Renaming A Child`_
9. `Other Utilities`_
10. `Debugging and Testing Features`_
7. `Other Useful Pages`_
8. `Static Files in /public_html`_
-9. `Safety and security issues -- names vs. URIs`_
+9. `Safety and Security Issues -- Names vs. URIs`_
10. `Concurrency Issues`_
+11. `Access Blacklist`_
+
Enabling the web-API port
=========================
option to the 'tahoe create-node' command. By default, the node listens on
port 3456, on the loopback (127.0.0.1) interface.
+
Basic Concepts: GET, PUT, DELETE, POST
======================================
operations are required to have no side-effects.
PUT is used to upload new objects into the filesystem, or to replace an
-existing object. DELETE it used to delete objects from the filesystem. Both
-PUT and DELETE are required to be idempotent: performing the same operation
-multiple times must have the same side-effects as only performing it once.
+existing link or the contents of a mutable file. DELETE is used to unlink
+objects from directories. Both PUT and DELETE are required to be idempotent:
+performing the same operation multiple times must have the same side-effects
+as only performing it once.
POST is used for more complicated actions that cannot be expressed as a GET,
PUT, or DELETE. POST operations can be thought of as a method call: sending
some message to the object referenced by the URL. In Tahoe, POST is also used
for operations that must be triggered by an HTML form (including upload and
-delete), because otherwise a regular web browser has no way to accomplish
+unlinking), because otherwise a regular web browser has no way to accomplish
these tasks. In general, everything that can be done with a PUT or DELETE can
also be done with a POST.
expected to use the RESTful interface described above. The second is a human
using a standard web browser to work with the filesystem. This user is given
a series of HTML pages with links to download files, and forms that use POST
-actions to upload, rename, and delete files.
+actions to upload, rename, and unlink files.
When an error occurs, the HTTP response code will be set to an appropriate
400-series code (like 404 Not Found for an unknown childname, or 400 Bad Request
``text/*``, or text/html (or if there is no Accept header), HTML tracebacks will
be generated.
+
URLs
====
the security properties of Tahoe caps to be extended across the web-API
interface.
+
Slow Operations, Progress, and Cancelling
=========================================
handles. Instead, they emit line-oriented status results immediately. Client
code can cancel the operation by simply closing the HTTP connection.
+
Programmatic Operations
=======================
that use HTTP to communicate with a Tahoe node. A later section describes
operations that are intended for web browsers.
+
Reading A File
--------------
"Browser Operations", for details on how to modify these URLs for that
purpose.
+
Writing/Uploading A File
------------------------
To use the /uri/$FILECAP form, $FILECAP must be a write-cap for a mutable file.
In the /uri/$DIRCAP/[SUBDIRS../]FILENAME form, if the target file is a
- writeable mutable file, that file's contents will be overwritten in-place. If
- it is a read-cap for a mutable file, an error will occur. If it is an
- immutable file, the old file will be discarded, and a new one will be put in
- its place.
+ writeable mutable file, that file's contents will be overwritten
+ in-place. If it is a read-cap for a mutable file, an error will occur.
+ If it is an immutable file, the old file will be discarded, and a new
+ one will be put in its place. If the target file is a writable mutable
+ file, you may also specify an "offset" parameter -- a byte offset that
+ determines where in the mutable file the data from the HTTP request
+ body is placed. This operation is relatively efficient for MDMF mutable
+ files, and is relatively inefficient (but still supported) for SDMF
+ mutable files. If no offset parameter is specified, then the entire
+ file is replaced with the data from the HTTP request body. For an
+ immutable file, the "offset" parameter is not valid.
When creating a new file, if "mutable=true" is in the query arguments, the
operation will create a mutable file instead of an immutable one.
If "mutable=true" is in the query arguments, the operation will create a
mutable file, and return its write-cap in the HTTP respose. The default is
- to create an immutable file, returning the read-cap as a response.
+ to create an immutable file, returning the read-cap as a response. If
+ you create a mutable file, you can also use the "mutable-type" query
+ parameter. If "mutable-type=sdmf", then the mutable file will be created
+ in the old SDMF mutable file format. This is desirable for files that
+ need to be read by old clients. If "mutable-type=mdmf", then the file
+ will be created in the new MDMF mutable file format. MDMF mutable files
+ can be downloaded more efficiently, and modified in-place efficiently,
+ but are not compatible with older versions of Tahoe-LAFS. If no
+ "mutable-type" argument is given, the file is created in whatever
+ format was configured in tahoe.cfg.
+
Creating A New Directory
------------------------
This operation will return an error if the parent directory is immutable,
or already has a child named NAME.
-Get Information About A File Or Directory (as JSON)
----------------------------------------------------
+
+Getting Information About A File Or Directory (as JSON)
+-------------------------------------------------------
``GET /uri/$FILECAP?t=json``
time.
-Attaching an existing File or Directory by its read- or write-cap
+Attaching an Existing File or Directory by its read- or write-cap
-----------------------------------------------------------------
``PUT /uri/$DIRCAP/[SUBDIRS../]CHILDNAME?t=uri``
would result in granting the cap's write authority to holders of the
directory read cap.
-Adding multiple files or directories to a parent directory at once
+
+Adding Multiple Files or Directories to a Parent Directory at Once
------------------------------------------------------------------
``POST /uri/$DIRCAP/[SUBDIRS..]?t=set_children``
backward compatibility should continue to use "set_children".
-Deleting a File or Directory
-----------------------------
+Unlinking a File or Directory
+-----------------------------
``DELETE /uri/$DIRCAP/[SUBDIRS../]CHILDNAME``
be modified.
Note that this does not actually delete the file or directory that the name
- points to from the tahoe grid -- it only removes the named reference from
+ points to from the tahoe grid -- it only unlinks the named reference from
this directory. If there are other names in this directory or in other
directories that point to the resource, then it will remain accessible
through those paths. Even if all names pointing to this object are removed
This method returns the file- or directory- cap of the object that was just
removed.
+
Browser Operations: Human-oriented interfaces
=============================================
specified by using <input type="hidden"> elements. For clarity, the
descriptions below display the most significant arguments as URL query args.
+
Viewing A Directory (as HTML)
-----------------------------
browser, which contains HREF links to all files and directories reachable
from this directory. These HREF links do not have a t= argument, meaning
that a human who follows them will get pages also meant for a human. It also
- contains forms to upload new files, and to delete files and directories.
- Those forms use POST methods to do their job.
+ contains forms to upload new files, and to unlink files and directories
+ from their parent directory. Those forms use POST methods to do their job.
+
Viewing/Downloading a File
--------------------------
this form can *only* be used with file caps; it is an error to use a
directory cap after the /named/ prefix.
-Get Information About A File Or Directory (as HTML)
----------------------------------------------------
+
+Getting Information About A File Or Directory (as HTML)
+-------------------------------------------------------
``GET /uri/$FILECAP?t=info``
* deep-check/deep-size/deep-stats/manifest (for directories)
* replace-conents form (for mutable files)
+
Creating a Directory
--------------------
If a "mutable=true" argument is provided, the operation will create a
mutable file, and the response body will contain the write-cap instead of
the upload results page. The default is to create an immutable file,
- returning the upload results page as a response.
+ returning the upload results page as a response. If you create a
+ mutable file, you may choose to specify the format of that mutable file
+ with the "mutable-type" parameter. If "mutable-type=mdmf", then the
+ file will be created as an MDMF mutable file. If "mutable-type=sdmf",
+ then the file will be created as an SDMF mutable file. If no value is
+ specified, the file will be created in whatever format is specified in
+ tahoe.cfg.
``POST /uri/$DIRCAP/[SUBDIRS../]?t=upload``
the "PUT /uri/$FILECAP" form, but uses a POST for the benefit of HTML forms
in a web browser.
+
Attaching An Existing File Or Directory (by URI)
------------------------------------------------
This accepts the same replace= argument as POST t=upload.
-Deleting A Child
-----------------
+
+Unlinking A Child
+-----------------
``POST /uri/$DIRCAP/[SUBDIRS../]?t=delete&name=CHILDNAME``
+``POST /uri/$DIRCAP/[SUBDIRS../]?t=unlink&name=CHILDNAME``
+
This instructs the node to remove a child object (file or subdirectory) from
the given directory, which must be mutable. Note that the entire subtree is
unlinked from the parent. Unlike deleting a subdirectory in a UNIX local
into the subtree will see that the child subdirectories are not modified by
this operation. Only the link from the given directory to its child is severed.
+ In Tahoe-LAFS v1.9.0 and later, t=unlink can be used as a synonym for t=delete.
+ If interoperability with older web-API servers is required, t=delete should
+ be used.
+
+
Renaming A Child
----------------
If the object is an immutable file, this will return the same value as
t=uri.
+
Debugging and Testing Features
------------------------------
was untraversable, since the manifest entry is emitted to the HTTP response
body before the child is traversed.
+
Other Useful Pages
==================
prettier front-end to the rest of the Tahoe web-API.
-Safety and security issues -- names vs. URIs
+Safety and Security Issues -- Names vs. URIs
============================================
Summary: use explicit file- and dir- caps whenever possible, to reduce the
directory) is found by following this name (or sequence of names) when my
request reaches the server". Use URIs if you want "this particular object".
+
Concurrency Issues
==================
Coordination Directive" sections of `mutable.rst <../specifications/mutable.rst>`_.
+Access Blacklist
+================
+
+Gateway nodes may find it necessary to prohibit access to certain files. The
+web-API has a facility to block access to filecaps by their storage index,
+returning a 403 "Forbidden" error instead of the original file.
+
+This blacklist is recorded in $NODEDIR/access.blacklist, and contains one
+blocked file per line. Comment lines (starting with ``#``) are ignored. Each
+line consists of the storage-index (in the usual base32 format as displayed
+by the "More Info" page, or by the "tahoe debug dump-cap" command), followed
+by whitespace, followed by a reason string, which will be included in the 403
+error message. This could hold a URL to a page that explains why the file is
+blocked, for example.
+
+So for example, if you found a need to block access to a file with filecap
+``URI:CHK:n7r3m6wmomelk4sep3kw5cvduq:os7ijw5c3maek7pg65e5254k2fzjflavtpejjyhshpsxuqzhcwwq:3:20:14861``,
+you could do the following::
+
+ tahoe debug dump-cap URI:CHK:n7r3m6wmomelk4sep3kw5cvduq:os7ijw5c3maek7pg65e5254k2fzjflavtpejjyhshpsxuqzhcwwq:3:20:14861
+ -> storage index: whpepioyrnff7orecjolvbudeu
+ echo "whpepioyrnff7orecjolvbudeu my puppy told me to" >>$NODEDIR/access.blacklist
+ tahoe restart $NODEDIR
+ tahoe get URI:CHK:n7r3m6wmomelk4sep3kw5cvduq:os7ijw5c3maek7pg65e5254k2fzjflavtpejjyhshpsxuqzhcwwq:3:20:14861
+ -> error, 403 Access Prohibited: my puppy told me to
+
+The ``access.blacklist`` file will be checked each time a file or directory
+is accessed: the file's ``mtime`` is used to decide whether it need to be
+reloaded. Therefore no node restart is necessary when creating the initial
+blacklist, nor when adding second, third, or additional entries to the list.
+When modifying the file, be careful to update it atomically, otherwise a
+request may arrive while the file is only halfway written, and the partial
+file may be incorrectly parsed.
+
+The blacklist is applied to all access paths (including FTP, SFTP, and CLI
+operations), not just the web-API. The blacklist also applies to directories.
+If a directory is blacklisted, the gateway will refuse access to both that
+directory and any child files/directories underneath it, when accessed via
+"DIRCAP/SUBDIR/FILENAME" -style URLs. Users who go directly to the child
+file/dir will bypass the blacklist.
+
+The node will log the SI of the file being blocked, and the reason code, into
+the ``logs/twistd.log`` file.
+
+
.. [1] URLs and HTTP and UTF-8, Oh My
HTTP does not provide a mechanism to specify the character set used to
projects / tahoe-lafs / tahoe-lafs.git / blobdiff