Add --replace as a command

tests.json

@@ -2230,5 +2230,130 @@
             "stderr": true,
             "returncode": 9
         }
-    }
+    },
+    {
+        "input": {
+            "arguments": [
+                "http://test.org/?key=val",
+                "--replace",
+                "key=foo"
+            ]
+        },
+        "expected": {
+            "stdout": "http://test.org/?key=foo\n",
+            "stderr": "",
+            "returncode": 0
+        }
+    },
+    {
+        "input": {
+            "arguments": [
+                "http://test.org/?that=thing&key=val",
+                "--replace",
+                "key=foo"
+            ]
+        },
+        "expected": {
+            "stdout": "http://test.org/?that=thing&key=foo\n",
+            "stderr": "",
+            "returncode": 0
+        }
+    },
+    {
+        "input": {
+            "arguments": [
+                "http://test.org/?that=thing&key",
+                "--replace",
+                "key=foo"
+            ]
+        },
+        "expected": {
+            "stdout": "http://test.org/?that=thing&key=foo\n",
+            "stderr": "",
+            "returncode": 0
+        }
+    },
+    {
+        "input": {
+            "arguments": [
+                "http://test.org/?that=thing&key=foo",
+                "--replace",
+                "key"
+            ]
+        },
+        "expected": {
+            "stdout": "http://test.org/?that=thing&key\n",
+            "stderr": "",
+            "returncode": 0
+        }
+    },
+    {
+        "input": {
+            "arguments": [
+                "https://example.com?a=123&b=321&b=987",
+                "--replace",
+                "b=foo"
+            ]
+        },
+        "expected": {
+            "stdout": "https://example.com/?a=123&b=foo\n",
+            "stderr": "",
+            "returncode": 0
+        }
+    },
+    {
+        "input": {
+            "arguments": [
+                "example.org/?quest=best",
+                "--replace",
+                "quest=%00",
+                "--json"
+            ]
+        },
+        "expected": {
+			"stdout": [{
+				"url": "http://example.org/?quest=%00",
+				"parts": {
+					"scheme": "http",
+					"host": "example.org",
+					"path": "/"
+				},
+				"params": [
+					{
+						"key": "quest",
+						"value": "\u0000"
+					}
+				]
+			}],
+			"stderr": "",
+            "returncode": 0
+        }
+    },
+    {
+        "input": {
+            "arguments": [
+                "example.com",
+                "--replace"
+            ]
+        }, 
+        "expected": {
+            "stderr": "trurl error: No data passed to replace component\ntrurl error: Try trurl -h for help\n",
+            "stdout":"",
+            "returncode": 12
+        }
+    },
+    {
+    "input": {
+            "arguments": [
+                "http://test.org/?that=thing",
+                "--force-replace",
+                "key=foo"
+            ]
+        },
+        "expected": {
+            "stdout": "http://test.org/?that=thing&key=foo\n",
+            "stderr": "trurl note: key 'key' not in url, appending to query\n",
+            "returncode": 0
+        }
+  }
 ]

trurl.1

@@ -196,6 +196,15 @@ properly.
 Redirect the URL to this new location.
 The redirection is performed on the base URL, so, if no base URL is specified,
 no redirection will be performed.
+.IP "--replace [data]"
+Replaces a URL query.
+
+data can either take the form of a single value, or as a key/value pair in the
+shape \fIfoo=bar\fP. If replace is called on an item that isn't in the list of
+queries trurl will ignore that item.
+.IP "--force-replace [data]"
+Works the same as \fI--replace\fP, but trurl will append a missing query string if 
+it is not in the query list already.
 .IP "-s, --set [component][:]=[data]"
 Set this URL component. Setting blank string ("") will clear the component
 from the URL.

trurl.c

@@ -129,6 +129,7 @@ static const struct var variables[] = {
 #define ERROR_BADURL 9 /* if --verify is set and the URL cannot parse */
 #define ERROR_GET   10 /* bad --get syntax */
 #define ERROR_ITER  11 /* bad --iterate syntax */
+#define ERROR_REPL  12 /* a --replace problem */
 
 #ifndef SUPPORTS_URL_STRERROR
 /* provide a fake local mockup */
@@ -181,6 +182,8 @@ static void help(void)
     "      --as-idn                     - encode hostnames in idn\n"
     "      --query-separator [letter]   - if something else than '&'\n"
     "      --redirect [URL]             - redirect to this\n"
+    "      --replace [data]             - replaces a query [data]\n"
+    "      --force-replace [data]       - appends a new query if not found\n"
     "  -s, --set [component]=[data]     - set component content\n"
     "      --sort-query                 - alpha-sort the query pairs\n"
     "      --trim [component]=[what]    - trim component\n"
@@ -262,6 +265,7 @@ struct option {
   struct curl_slist *set_list;
   struct curl_slist *trim_list;
   struct curl_slist *iter_list;
+  struct curl_slist *replace_list;
   const char *redirect;
   const char *qsep;
   const char *format;
@@ -280,6 +284,7 @@ struct option {
   bool urlencode;
   bool end_of_options;
   bool quiet_warnings;
+  bool force_replace;
 
   /* -- stats -- */
   unsigned int urls;
@@ -311,6 +316,7 @@ static void trurl_cleanup_options(struct option *o)
   curl_slist_free_all(o->iter_list);
   curl_slist_free_all(o->append_query);
   curl_slist_free_all(o->trim_list);
+  curl_slist_free_all(o->replace_list);
   curl_slist_free_all(o->append_path);
 }
 
@@ -458,6 +464,18 @@ static void trimadd(struct option *o,
     o->trim_list = n;
 }
 
+static void replaceadd(struct option *o,
+                       const char *replace_list) /* [component]=[data] */
+{
+  struct curl_slist *n = NULL;
+  if(replace_list)
+    n = curl_slist_append(o->replace_list, replace_list);
+  else
+    errorf(o, ERROR_REPL, "No data passed to replace component");
+
+  if(n)
+    o->replace_list = n;
+}
 static bool checkoptarg(struct option *o, const char *str,
                         const char *given,
                         const char *arg)
@@ -574,6 +592,15 @@ static int getarg(struct option *o,
     o->urlencode = true;
   else if(!strcmp("--quiet", flag))
     o->quiet_warnings = true;
+  else if(!strcmp("--replace", flag)) {
+    replaceadd(o, arg);
+    *usedarg = true;
+  }
+  else if(!strcmp("--force-replace", flag)) {
+    replaceadd(o, arg);
+    o->force_replace = true;
+    *usedarg = true;
+  }
   else
     return 1;  /* unrecognized option */
   return 0;
@@ -1222,6 +1249,60 @@ static void sortquery(struct option *o)
   }
 }
 
+static void replace(struct option *o)
+{
+  struct curl_slist *node;
+  for(node = o->replace_list; node; node = node->next) {
+    struct string key;
+    struct string value;
+    bool replaced = false;
+    int i;
+    key.str = node->data;
+    value.str = strchr(key.str, '=');
+    if(value.str) {
+      key.len = value.str++ - key.str;
+      value.len = strlen(value.str);
+    }
+    else {
+      key.len = strlen(key.str);
+      value.str = NULL;
+      value.len = 0;
+    }
+    for(i = 0; i < nqpairs; i++) {
+      char *q = qpairs[i].str;
+      /* not the correct query, move on */
+      if(strncmp(q, key.str, key.len))
+        continue;
+      free(qpairs[i].str);
+      curl_free(qpairsdec[i].str);
+      /* this is a duplicate remove it. */
+      if(replaced) {
+        qpairs[i].len = 0;
+        qpairs[i].str = strdup("");
+        qpairsdec[i].len = 0;
+        qpairsdec[i].str = strdup("");
+        continue;
+      }
+      struct string *pdec =
+        memdupdec(key.str, key.len + value.len + 1, o->jsonout);
+      struct string *p = memdupzero(key.str, key.len + value.len + 1);
+      qpairs[i].len = p->len;
+      qpairs[i].str = p->str;
+      qpairsdec[i].len = pdec->len;
+      qpairsdec[i].str = pdec->str;
+      free(pdec);
+      free(p);
+      replaced = true;
+    }
+
+    if(!replaced && o->force_replace) {
+      trurl_warnf(o, "key '%.*s' not in url, appending to query",
+                  (int) (key.len),
+                  key.str);
+      addqpair(key.str, strlen(key.str), o->jsonout);
+    }
+  }
+}
 static CURLUcode seturl(struct option *o, CURLU *uh, const char *url)
 {
   return curl_url_set(uh, CURLUPART_URL, url,
@@ -1371,6 +1452,9 @@ static void singleurl(struct option *o,
     /* trim parts */
     trim(o);
 
+    /* replace parts */
+    replace(o);
+
     /* append query segments */
     for(p = o->append_query; p; p = p->next) {
       addqpair(p->data, strlen(p->data), o->jsonout);