From: Zooko O'Whielacronx Date: Sat, 11 Apr 2009 22:48:28 +0000 (-0700) Subject: docs: webapi.txt edits to explain a few things better, adjust indentation, editing X-Git-Tag: allmydata-tahoe-1.4.0~13 X-Git-Url: https://git.rkrishnan.org/components/com_hotproperty/%22doc.html/readonly?a=commitdiff_plain;h=664b69dd8db5892eb691e14e774c332fc5791d4a;p=tahoe-lafs%2Ftahoe-lafs.git docs: webapi.txt edits to explain a few things better, adjust indentation, editing --- diff --git a/docs/frontends/webapi.txt b/docs/frontends/webapi.txt index 658524fb..082a4c46 100644 --- a/docs/frontends/webapi.txt +++ b/docs/frontends/webapi.txt @@ -381,12 +381,24 @@ GET /uri/$DIRCAP/[SUBDIRS../]SUBDIR?t=json GET /uri/$DIRCAP/[SUBDIRS../]FILENAME?t=json This returns a machine-parseable JSON-encoded description of the given - object. The JSON always contains a list, and the first element of the list - is always a flag that indicates whether the referenced object is a file or a - directory. If it is a file, then the information includes file size and URI, - like this: + object. The JSON always contains a list, and the first element of the list is + always a flag that indicates whether the referenced object is a file or a + directory. If it is a capability to a file, then the information includes + file size and URI, like this: GET /uri/$FILECAP?t=json : + + [ "filenode", { + "ro_uri": file_uri, + "verify_uri": verify_uri, + "size": bytes, + "mutable": false, + } ] + + If it is a capability to a directory followed by a path from that directory + to a file, then the information also includes metadata from the link to the + file in the parent directory, like this: + GET /uri/$DIRCAP/[SUBDIRS../]FILENAME?t=json : [ "filenode", { "ro_uri": file_uri, @@ -446,26 +458,26 @@ GET /uri/$DIRCAP/[SUBDIRS../]FILENAME?t=json PUT /uri/$DIRCAP/[SUBDIRS../]CHILDNAME?t=uri - This attaches a child object (either a file or directory) to a specified - location in the virtual filesystem. The child object is referenced by its - read- or write- cap, as provided in the HTTP request body. This will create - intermediate directories as necessary. + This attaches a child object (either a file or directory) to a specified + location in the virtual filesystem. The child object is referenced by its + read- or write- cap, as provided in the HTTP request body. This will create + intermediate directories as necessary. - This is similar to a UNIX hardlink: by referencing a previously-uploaded - file (or previously-created directory) instead of uploading/creating a new - one, you can create two references to the same object. + This is similar to a UNIX hardlink: by referencing a previously-uploaded file + (or previously-created directory) instead of uploading/creating a new one, + you can create two references to the same object. - The read- or write- cap of the child is provided in the body of the HTTP - request, and this same cap is returned in the response body. + The read- or write- cap of the child is provided in the body of the HTTP + request, and this same cap is returned in the response body. - The default behavior is to overwrite any existing object at the same - location. To prevent this (and make the operation return an error instead of - overwriting), add a "replace=false" argument, as "?t=uri&replace=false". - With replace=false, this operation will return an HTTP 409 "Conflict" error - if there is already an object at the given location, rather than overwriting - the existing object. Note that "true", "t", and "1" are all synonyms for - "True", and "false", "f", and "0" are synonyms for "False". the parameter is - case-insensitive. + The default behavior is to overwrite any existing object at the same + location. To prevent this (and make the operation return an error instead of + overwriting), add a "replace=false" argument, as "?t=uri&replace=false". With + replace=false, this operation will return an HTTP 409 "Conflict" error if + there is already an object at the given location, rather than overwriting the + existing object. Note that "true", "t", and "1" are all synonyms for "True", + and "false", "f", and "0" are synonyms for "False". the parameter is + case-insensitive. === Deleting a File or Directory === @@ -1364,24 +1376,23 @@ prettier front-end to the rest of the Tahoe wapi. == safety and security issues -- names vs. URIs == Summary: use explicit file- and dir- caps whenever possible, to reduce the -potential for surprises when the virtual drive is changed while you aren't -looking. +potential for surprises when the filesystem structure is changed. -The vdrive provides a mutable filesystem, but the ways that the filesystem -can change are limited. The only thing that can change is that the mapping -from child names to child objects that each directory contains can be changed -by adding a new child name pointing to an object, removing an existing child -name, or changing an existing child name to point to a different object. +Tahoe provides a mutable filesystem, but the ways that the filesystem can +change are limited. The only thing that can change is that the mapping from +child names to child objects that each directory contains can be changed by +adding a new child name pointing to an object, removing an existing child name, +or changing an existing child name to point to a different object. -Obviously if you query tahoe for information about the filesystem and then -act upon the filesystem (such as by getting a listing of the contents of a +Obviously if you query Tahoe for information about the filesystem and then act +to change the filesystem (such as by getting a listing of the contents of a directory and then adding a file to the directory), then the filesystem might -have been changed after you queried it and before you acted upon it. -However, if you use the URI instead of the pathname of an object when you act -upon the object, then the only change that can happen is when the object is a -directory then the set of child names it has might be different. If, on the -other hand, you act upon the object using its pathname, then a different -object might be in that place, which can result in more kinds of surprises. +have been changed after you queried it and before you acted upon it. However, +if you use the URI instead of the pathname of an object when you act upon the +object, then the only change that can happen is if the object is a directory +then the set of child names it has might be different. If, on the other hand, +you act upon the object using its pathname, then a different object might be in +that place, which can result in more kinds of surprises. For example, suppose you are writing code which recursively downloads the contents of a directory. The first thing your code does is fetch the listing