Add BigQuery Adapter (#125)

README.markdown

@@ -8,6 +8,7 @@ take on [dbext.vim][], improving on it on the following ways:
 * All interaction is through invoking `:DB`, not 53 different commands and 35
   different maps (omitting many of the more esoteric features, of course)
 * Supports a modern array of backends, including NoSQL databases:
+  - Big Query
   - ClickHouse
   - Impala
   - jq

autoload/db.vim

@@ -331,8 +331,13 @@ function! db#connect(url) abort
   endif
   let pattern = db#adapter#call(url, 'auth_pattern', [], 'auth\|login')
   try
-    call writefile(split(db#adapter#call(url, 'auth_input', [], "\n"), "\n", 1), input, 'b')
-    let [out, exit_status] = call('s:systemlist', filter)
+    let auth_input = db#adapter#call(url, 'auth_input', [], "\n")
+    " Short-circuit the authentication if unnecessary for the adapter
+    if auth_input == v:false
+      return url
+    endif
+    call writefile(split(auth_input, "\n", 1), input, 'b')
+    let [out, exit_status] = call('s:systemlist', s:filter(url, input))
     if exit_status && join(out, "\n") =~? pattern && resolved =~# '^[^:]*://[^:/@]*@'
       let password = inputsecret('Password: ')
       let url = substitute(resolved, '://[^:/@]*\zs@', ':'.db#url#encode(password).'@', '')

autoload/db/adapter/bigquery.vim

@@ -0,0 +1,34 @@
+function! db#adapter#bigquery#auth_input() abort
+  return v:false
+endfunction
+
+function! s:command_for_url(url, subcmd) abort
+  let cmd = ['bq']
+  let parsed = db#url#parse(a:url)
+  if has_key(parsed, 'opaque')
+    let host_targets = split(substitute(parsed.opaque, '/', '', 'g'), ':')
+
+    " If the host is specified as bigquery:project:dataset, then parse
+    " the optional (project, dataset) to supply them to the CLI.
+    if len(host_targets) == 2
+      call add(cmd, '--project_id=' . host_targets[0])
+      call add(cmd, '--dataset_id=' . host_targets[1])
+    elseif len(host_targets) == 1
+      call add(cmd, '--project_id=' . host_targets[0])
+    endif
+  endif
+
+  for [k, v] in items(parsed.params)
+    let op = '--'.k.'='.v
+    call add(cmd, op)
+  endfor
+  return cmd + [a:subcmd]
+endfunction
+
+function! db#adapter#bigquery#filter(url) abort
+  return s:command_for_url(a:url, 'query')
+endfunction
+
+function! db#adapter#bigquery#interactive(url) abort
+  return s:command_for_url(a:url, 'shell')
+endfunction

doc/dadbod.txt

@@ -81,6 +81,17 @@ Handling these parameters is up to the individual adapters.  By default,
 unrecognized parameters are ignored.  Pass Boolean parameters as the literal
 strings "true" and "false" (e.g., `?ssl=true`).
 
+                                                *dadbod-bigquery*
+bigquery ~
+>
+    bigquery:[<project_id>[:<dataset_id>]][?...]
+    bigquery:?project_id=<project_id>&dataset_id=<dataset_id>[&...]
+<
+
+The first form of the URL assumes your default dataset belongs to your default project.  If it doesn't, use the second form.
+
+Additional query parameters can be any valid global flag, for example, `&disable_ssl_validation=true`.  Note that subcommand flags are not supported as query parameters, but they can be specified in `~/.bigqueryrc`.
+
                                                 *dadbod-dbext*
 dbext ~
 >