MINOR: sample: converter: Add json_query converter

With the json_query can a JSON value be extacted from a header
or body of the request and saved to a variable.

This converter makes it possible to handle some JSON workload
to route requests to different backends.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index f242300e7f596adfb19b1d24c15b42e490e92890..61c2a6dd9c77c20501994f30744d8f12f63a388c 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -15961,6 +15961,30 @@ json([<input-code>])
   Output log:
      {"ip":"127.0.0.1","user-agent":"Very \"Ugly\" UA 1\/2"}
 
+json_query(<json_path>,[<output_type>])
+  The json_query converter supports the JSON types string, boolean and
+  number. Floating point numbers will be returned as a string. By
+  specifying the output_type 'int' the value will be converted to an
+  Integer. If conversion is not possible the json_query converter fails.
+
+  <json_path> must be a valid JSON Path string as defined in
+  https://datatracker.ietf.org/doc/draft-ietf-jsonpath-base/
+
+  Example:
+     # get a integer value from the request body
+     # "{"integer":4}" => 5
+     http-request set-var(txn.pay_int) req.body,json_query('$.integer','int'),add(1)
+
+     # get a key with '.' in the name
+     # {"my.key":"myvalue"} => myvalue
+     http-request set-var(txn.pay_mykey) req.body,json_query('$.my\\.key')
+
+     # {"boolean-false":false} => 0
+     http-request set-var(txn.pay_boolean_false) req.body,json_query('$.boolean-false')
+
+     # get the value of the key 'iss' from a JWT Bearer token
+     http-request set-var(txn.token_payload) req.hdr(Authorization),word(2,.),ub64dec,json_query('$.iss')
+
 language(<value>[,<default>])
   Returns the value with the highest q-factor from a list as extracted from the
   "accept-language" header using "req.fhdr". Values with no q-factor have a

diff --git a/reg-tests/converter/json_query.vtc b/reg-tests/converter/json_query.vtc
new file mode 100644 (file)
index 0000000..ade7b4c
--- /dev/null
+++ b/reg-tests/converter/json_query.vtc
@@ -0,0 +1,95 @@
+varnishtest "JSON Query converters Test"
+#REQUIRE_VERSION=2.4
+
+feature ignore_unknown_macro
+
+server s1 {
+       rxreq
+       txresp
+} -repeat 8 -start
+
+haproxy h1 -conf {
+    defaults
+       mode http
+       timeout connect 1s
+       timeout client  1s
+       timeout server  1s
+       option http-buffer-request
+
+    frontend fe
+       bind "fd@${fe}"
+       tcp-request inspect-delay 1s
+
+       http-request set-var(sess.header_json) req.hdr(Authorization),json_query('$.iss')
+       http-request set-var(sess.pay_json) req.body,json_query('$.iss')
+       http-request set-var(sess.pay_int) req.body,json_query('$.integer',"int"),add(1)
+       http-request set-var(sess.pay_neg_int) req.body,json_query('$.negativ-integer',"int"),add(1)
+       http-request set-var(sess.pay_double) req.body,json_query('$.double')
+       http-request set-var(sess.pay_boolean_true) req.body,json_query('$.boolean-true')
+       http-request set-var(sess.pay_boolean_false) req.body,json_query('$.boolean-false')
+       http-request set-var(sess.pay_mykey) req.body,json_query('$.my\\.key')
+
+       http-response set-header x-var_header %[var(sess.header_json)]
+       http-response set-header x-var_body %[var(sess.pay_json)]
+       http-response set-header x-var_body_int %[var(sess.pay_int)]
+       http-response set-header x-var_body_neg_int %[var(sess.pay_neg_int)]
+       http-response set-header x-var_body_double %[var(sess.pay_double)]
+       http-response set-header x-var_body_boolean_true %[var(sess.pay_boolean_true)]
+       http-response set-header x-var_body_boolean_false %[var(sess.pay_boolean_false)]
+       http-response set-header x-var_body_mykey %[var(sess.pay_mykey)]
+
+       default_backend be
+
+    backend be
+       server s1 ${s1_addr}:${s1_port}
+} -start
+
+client c1 -connect ${h1_fe_sock} {
+       txreq -url "/" \
+         -hdr "Authorization: {\"iss\":\"kubernetes.io/serviceaccount\"}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_header ~ "kubernetes.io/serviceaccount"
+
+       txreq -url "/" \
+         -body "{\"iss\":\"kubernetes.io/serviceaccount\"}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_body ~ "kubernetes.io/serviceaccount"
+
+       txreq -url "/" \
+         -body "{\"integer\":4}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_body_int ~ "5"
+
+       txreq -url "/" \
+         -body "{\"integer\":-4}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_body_int ~ "-3"
+
+       txreq -url "/" \
+         -body "{\"double\":4.5}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_body_double ~ "4.5"
+
+       txreq -url "/" \
+         -body "{\"boolean-true\":true}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_body_boolean_true == 1
+
+       txreq -url "/" \
+         -body "{\"boolean-false\":false}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_body_boolean_false == 0
+
+       txreq -url "/" \
+         -body "{\"my.key\":\"myvalue\"}"
+       rxresp
+       expect resp.status == 200
+       expect resp.http.x-var_body_mykey ~ "myvalue"
+} -run
\ No newline at end of file

diff --git a/src/sample.c b/src/sample.c
index 7337ba06a9b2efaf432f970e293ef32d8c9cf970..728c7c76d15257438948be178d744f4bcac3f31f 100644 (file)
--- a/src/sample.c
+++ b/src/sample.c
@@ -16,6 +16,7 @@
 #include <arpa/inet.h>
 #include <stdio.h>
 
+#include <import/mjson.h>
 #include <import/sha1.h>
 #include <import/xxhash.h>
 
@@ -3689,6 +3690,92 @@ static int sample_conv_rtrim(const struct arg *arg_p, struct sample *smp, void *
        return 1;
 }
 
+/* This function checks the "json_query" converter's arguments. */
+static int sample_check_json_query(struct arg *arg, struct sample_conv *conv,
+                           const char *file, int line, char **err)
+{
+       if (arg[0].data.str.data == 0) {
+               memprintf(err, "json_path must not be empty");
+               return 0;
+       }
+
+       if (arg[1].data.str.data != 0) {
+               if (strcmp(arg[1].data.str.area, "int") != 0) {
+                       memprintf(err, "output_type only supports \"int\" as argument");
+                       return 0;
+               } else {
+                       arg[1].type = ARGT_SINT;
+                       arg[1].data.sint = 0;
+               }
+       }
+       return 1;
+}
+
+/* Limit JSON integer values to the range [-(2**53)+1, (2**53)-1] as per
+ * the recommendation for interoperable integers in section 6 of RFC 7159.
+ */
+#define JSON_INT_MAX ((1LL << 53) - 1)
+#define JSON_INT_MIN (-JSON_INT_MAX)
+
+/* This sample function get the value from a given json string.
+ * The mjson library is used to parse the JSON struct
+ */
+static int sample_conv_json_query(const struct arg *args, struct sample *smp, void *private)
+{
+       struct buffer *trash = get_trash_chunk();
+       const char *p; /* holds the temporary string from mjson_find */
+       int tok, n;    /* holds the token enum and the length of the value */
+       int rc;        /* holds the return code from mjson_get_string */
+
+       tok = mjson_find(smp->data.u.str.area, smp->data.u.str.data, args[0].data.str.area, &p, &n);
+
+       switch(tok) {
+               case MJSON_TOK_NUMBER:
+                       if (args[1].type == ARGT_SINT) {
+                               smp->data.u.sint = atoll(p);
+
+                               if (smp->data.u.sint < JSON_INT_MIN || smp->data.u.sint > JSON_INT_MAX)
+                                       return 0;
+
+                               smp->data.type = SMP_T_SINT;
+                       } else {
+                               double double_val;
+                               if (mjson_get_number(smp->data.u.str.area, smp->data.u.str.data, args[0].data.str.area, &double_val) == 0) {
+                                       return 0;
+                               } else {
+                                       trash->data = snprintf(trash->area,trash->size,"%g",double_val);
+                                       smp->data.u.str = *trash;
+                                       smp->data.type = SMP_T_STR;
+                               }
+                       }
+                       break;
+               case MJSON_TOK_TRUE:
+                       smp->data.type = SMP_T_BOOL;
+                       smp->data.u.sint = 1;
+                       break;
+               case MJSON_TOK_FALSE:
+                       smp->data.type = SMP_T_BOOL;
+                       smp->data.u.sint = 0;
+                       break;
+               case MJSON_TOK_STRING:
+                       rc = mjson_get_string(smp->data.u.str.area, smp->data.u.str.data, args[0].data.str.area, trash->area, trash->size);
+                       if (rc == -1) {
+                               /* invalid string */
+                               return 0;
+                       } else {
+                               trash->data = rc;
+                               smp->data.u.str = *trash;
+                               smp->data.type = SMP_T_STR;
+                       }
+                       break;
+               default:
+                       /* no valid token found */
+                       return 0;
+       }
+       return 1;
+}
+
+
 /************************************************************************/
 /*       All supported sample fetch functions must be declared here     */
 /************************************************************************/
@@ -4203,6 +4290,7 @@ static struct sample_conv_kw_list sample_conv_kws = {ILH, {
        { "cut_crlf", sample_conv_cut_crlf,           0, NULL, SMP_T_STR,  SMP_T_STR  },
        { "ltrim",    sample_conv_ltrim,    ARG1(1,STR), NULL, SMP_T_STR,  SMP_T_STR  },
        { "rtrim",    sample_conv_rtrim,    ARG1(1,STR), NULL, SMP_T_STR,  SMP_T_STR  },
+       { "json_query", sample_conv_json_query, ARG2(1,STR,STR),  sample_check_json_query , SMP_T_STR, SMP_T_ANY },
        { NULL, NULL, 0, 0, 0 },
 }};