Implement HTTP POST

* NEWS: Update.
* doc/eclat.conf.5: Document http-method.  Reorganize description of
endpoints and regions.
* lib/libeclat.h (ec2_request) <postdata>: New member
(eclat_request_finalize): New proto.
* lib/req2url.c (eclat_request_to_url): Remove second argument.
All uses changed.
(eclat_request_finalize): New function.
* lib/reqfree.c: Free postdata.
* lib/reqsign.c (requestsign4): Implement post.
* src/config.c: New configuration statement http-method.
* src/eclat.c (use_post): New variable.
* src/eclat.h (use_post): New extern.
* src/util.c (eclat_send_request): Implement post.

1 files changed, 65 insertions, 48 deletions

diff --git a/doc/eclat.conf.5 b/doc/eclat.conf.5
index 4fa7102..32147e8 100644
--- a/doc/eclat.conf.5
+++ b/doc/eclat.conf.5
@@ -13,7 +13,7 @@
 .\"
 .\" You should have received a copy of the GNU General Public License
 .\" along with Eclat.  If not, see <http://www.gnu.org/licenses/>.
-.TH ECLAT.CONF 5 "January 22, 2015" "ECLAT" "Eclat User Reference"
+.TH ECLAT.CONF 5 "January 23, 2015" "ECLAT" "Eclat User Reference"
 .SH NAME
 eclat.conf \- configuration file for
 .BR eclat (1).
@@ -341,10 +341,23 @@ listed in the corresponding sections below.
 .SH EC2 CONFIGURATION
 The statements in this group configure EC2 endpoints and regions.
 .PP
-An \fBendpoint\fR is a URI of the Amazon server.  When selecting the
-endpoint to send the query to
-.B eclat
-uses the following algorithm:
+A \fIregion\fR determines physical location of servers supporting
+given AWS resources.
+.PP
+An \fIendpoint\fR is a URI of the Amazon server.  The endpoint to
+use is selected based on the region name.
+.TP
+\fBdefault\-endpoint\fR \fIhostname\fR;
+Defines the endpoint to use if no region-specific endpoint is
+configured.
+.TP
+\fBdefault\-region\fR \fIname\fR;
+Defines the name of the default region.
+.TP
+\fBregion\fR \fIname\fR \fIendpoint\fR;
+Declares a region and the corresponding endpoint.
+.PP
+The region is determined by the following algorithm:
 .nr step 1 1
 .IP \n[step]. 
 If the \fB\-\-region\fR option is given, take its argument as the
@@ -353,19 +366,17 @@ region name.
 If the \fBdefault\-region\fR statement is defined in the configuration
 file, use its argument as the region name.
 .IP \n+[step].
-If a region name is defined in one of the previous steps, select the
-endpoint defined in the \fBregion\fR statement with the corresponding
-name.
-.IP \n+[step].
-Otherwise, use the endpoint specified by the \fBdefault\-endpoint\fR
-statement.
-.TP
-\fBdefault\-endpoint\fR \fIhostname\fR;
-Defines the endpoint to use in the absence of the \fB\-\-region\fR
-option and \fBdefault\-region\fR statement.
-.TP
-\fBregion\fR \fIname\fR \fIendpoint\fR;
-Declares a region and the corresponding endpoint.
+Otherwise, attempt to obtain region from the \fIinstance store\fR.
+Obviously, this step can succeed only if \fBeclat\fR is run on an
+EC2 instance.
+.PP
+If none of these steps succeed, the program aborts.
+.PP
+Endpoint is selected by looking up a \fBregion\fR statement with
+the \fIname\fR argument matching the currently selected region.
+If such a statement is found, its \fIendpoint\fR argument defines
+the endpoint to use.  Otherwise, endpoint is taken from the
+\fBdefault\-endpoint\fR statement. 
 .PP
 An example of the EC2 endpoint configuration follows:
 .PP
@@ -378,37 +389,12 @@ region  us\-east\-1       ec2.us\-east\-1.amazonaws.com;
 #  US West (Oregon) Region
 region  us\-west\-2       ec2.us\-west\-2.amazonaws.com;
 .EE
-.SS AUTHENTICATION
+.SS HTTP METHOD
 .TP
-\fBauthentication\-provider\fR \fITYPE\fR [\fIARG\fR]\fB;\fR
-Defines authentication provider to use.  \fIAuthentication provider\fR
-is a service that supplies AWS access key ID and secret key.  See
-.BR eclat (1),
-section
-.BR AUTHENTICATION ,
-for a detailed description.
-
-The \fITYPE\fR argument defines the provider.  Allowed values are
-.BR file ,
-and
-.BR instance\-store .
-
-If \fITYPE\fR is \fBfile\fR, the \fIARG\fR parameter is treated as a
-shell globbing pattern: all files matching this pattern are attempted
-in turn, until a keypair is found in one of them.
-
-If \fITYPE\fR is \fBinstance\-store\fR, credentials will be obtained
-from the instance store.  \fIARG\fR is optional.  If supplied, it
-should be the name of the IAM role this instance is launched with.
-At the time of this writing, an instance can be associated with a
-single role, which will be used by default.
-.TP
-\fBaccess\-file\fR \fIname\fR;
-This is a shortcut for \fBauthentication\-provider file \fIname\fR.
-.TP
-\fBsignature\-version\fR \fIN\fR;
-Declares the signature version.  Valid values for \fIN\fR are \fB2\fR,
-which is the default, and \fB4\fR, which provides a better security.
+\fBhttp\-method\fR \fIARG\fR;
+Configures HTTP method.  Allowed values for \fIARG\fR are \fBGET\fR
+(the default), and \fBPOST\fR.  \fIARG\fR is case-insensitive.  The
+\fBPOST\fR method implies using signature version 4.
 .SS SSL CONFIGURATION
 The \fBssl\fR statement has two forms, and can be used as scalar or as
 a block statement.  In scalar form it is used to enable SSL:
@@ -448,6 +434,37 @@ By default the CA certificates shipped with
 .BR libcurl (3)
 will be used.  You would rarely need to use \fBca\-file\fR or
 \fBca\-path\fR statements.
+.SS AUTHENTICATION
+.TP
+\fBauthentication\-provider\fR \fITYPE\fR [\fIARG\fR]\fB;\fR
+Defines authentication provider to use.  \fIAuthentication provider\fR
+is a service that supplies AWS access key ID and secret key.  See
+.BR eclat (1),
+section
+.BR AUTHENTICATION ,
+for a detailed description.
+
+The \fITYPE\fR argument defines the provider.  Allowed values are
+.BR file ,
+and
+.BR instance\-store .
+
+If \fITYPE\fR is \fBfile\fR, the \fIARG\fR parameter is treated as a
+shell globbing pattern: all files matching this pattern are attempted
+in turn, until a keypair is found in one of them.
+
+If \fITYPE\fR is \fBinstance\-store\fR, credentials will be obtained
+from the instance store.  \fIARG\fR is optional.  If supplied, it
+should be the name of the IAM role this instance is launched with.
+At the time of this writing, an instance can be associated with a
+single role, which will be used by default.
+.TP
+\fBaccess\-file\fR \fIname\fR;
+This is a shortcut for \fBauthentication\-provider file \fIname\fR.
+.TP
+\fBsignature\-version\fR \fIN\fR;
+Declares the signature version.  Valid values for \fIN\fR are \fB2\fR,
+which is the default, and \fB4\fR, which provides a better security.
 .SH INSTANCE STORE CONFIGURATION
 The \fBinstance\-store\fR compound statement configures HTTP access to
 the instance store.  By default, \fBeclat\fR uses standard AWS values.