If broadcasting parent transaction of a ticket fails because it
references unknown outputs, there is a good chance that waiting a few
seconds will resolve the issue because the ancestor transactions will
propagate through the network and reach the mempool of the local dcrd
instance.
Rather than immediately returning an error if the cache is not
initialized, attempt to initialize it first. Without this change there
is only an attempt to initialize the cache once per minute.
A new middleware aborts any requests which require the data cache if the
cache is not yet initialized. An explicit error is returned so the admin
will be immediately aware what has gone wrong.
Previously, webpages were rendered and JSON responses were sent with
zero values, and with no indication of anything being wrong. This was
sometimes difficult to notice, and even when noticed the cause was not
immediately apparent.
Exporting this struct is a step towards breaking up the Start func into
a New func and Run func, enabling calling code to use:
api := webapi.New()
api.Run()
WebAPI is a more suitable name than server because it matches the
package name, and also it helps to distinguish WebAPI from the HTTP
server it uses internally (ie. webapi.server rather than server.server).
