* [9front] libjson can print invalid json @ 2022-11-17 21:52 Dave MacFarlane 2022-11-18 4:30 ` ori 0 siblings, 1 reply; 4+ messages in thread From: Dave MacFarlane @ 2022-11-17 21:52 UTC (permalink / raw) To: 9front print("%J", json); can print invalid json if a JSON string in the object has a quotation mark in it. I just threw together this patch to try and escape the strings from printjson() if anyone's interested in it. diff 30c5296f32b87d83529d772732726891e1261c9c uncommitted --- a/sys/src/libjson/printjson.c +++ b/sys/src/libjson/printjson.c @@ -52,6 +52,38 @@ } static int +printstring(Fmt *f, char *s) +{ + int slen = strlen(s); + int i, nq=0; + int r; + char *dup, lastq; + for(i = 0; i < slen; i++) + if (s[i] == '"') nq++; + + if (nq == 0) + return fmtprint(f, "\"%s\"", s); + + r = fmtprint(f, "\""); + + dup = strdup(s); + lastq = -1; + for(i = 0; i < slen; i++){ + if(dup[i] == '"') { + dup[i] = 0; + r += fmtprint(f, "%s\\\"", &dup[lastq+1]); + lastq = i; + } + } + + if (lastq != slen-1) + r += fmtprint(f, "%s", &dup[lastq+1]); + r += fmtprint(f, "\""); + free(dup); + return r; +} + +static int printjson(Fmt *f, JSON *j, int indent) { switch(j->t){ @@ -65,7 +97,7 @@ return fmtprint(f, "%f", j->n); break; case JSONString: - return fmtprint(f, "\"%s\"", j->s); + return printstring(f, j->s); break; case JSONArray: return printarray(f, j, indent+1); ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [9front] libjson can print invalid json 2022-11-17 21:52 [9front] libjson can print invalid json Dave MacFarlane @ 2022-11-18 4:30 ` ori 2022-11-18 14:37 ` Dave MacFarlane 0 siblings, 1 reply; 4+ messages in thread From: ori @ 2022-11-18 4:30 UTC (permalink / raw) To: 9front Quoth Dave MacFarlane <driusan@driusan.net>: > print("%J", json); can print invalid json if a JSON string in the object has a quotation mark in it. > > I just threw together this patch to try and escape the strings from printjson() if anyone's interested > in it. > > diff 30c5296f32b87d83529d772732726891e1261c9c uncommitted > --- a/sys/src/libjson/printjson.c > +++ b/sys/src/libjson/printjson.c > @@ -52,6 +52,38 @@ > } > > static int > +printstring(Fmt *f, char *s) > +{ > + int slen = strlen(s); > + int i, nq=0; > + int r; > + char *dup, lastq; > + for(i = 0; i < slen; i++) > + if (s[i] == '"') nq++; > + > + if (nq == 0) > + return fmtprint(f, "\"%s\"", s); > + > + r = fmtprint(f, "\""); > + > + dup = strdup(s); > + lastq = -1; > + for(i = 0; i < slen; i++){ > + if(dup[i] == '"') { > + dup[i] = 0; > + r += fmtprint(f, "%s\\\"", &dup[lastq+1]); > + lastq = i; > + } > + } > + > + if (lastq != slen-1) > + r += fmtprint(f, "%s", &dup[lastq+1]); > + r += fmtprint(f, "\""); > + free(dup); > + return r; > +} > + I think we have a problem with more than just quotes; we're not allowed any control characters, and we need to escape '\'; how's something like this (untested)? static int printstring(Fmt *f, char *s) { int n; n = 0; for(; *s; s++){ switch(*s){ case '\\': n += fmtstrcpy(f, "\\\\"); break; case '\f': n += fmtstrcpy(f, "\\f"); break; case '\b': n += fmtstrcpy(f, "\\b"); break; case '\n': n += fmtstrcpy(f, "\\n"); break; case '\r': n += fmtstrcpy(f, "\\r"); break; case '\"': n += fmtstrcpy(f, "\\\""); break; default: if(*s < 0x20) n += fmtprint(f, "\\u%04x", *s); else n += fmtrune(f, *s); } } return n; } ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [9front] libjson can print invalid json 2022-11-18 4:30 ` ori @ 2022-11-18 14:37 ` Dave MacFarlane 2022-11-18 14:52 ` Dave MacFarlane 0 siblings, 1 reply; 4+ messages in thread From: Dave MacFarlane @ 2022-11-18 14:37 UTC (permalink / raw) To: 9front It certainly looks more elegant than my code, but when I tested it it's missing the beginning and ending quote character of the json string. After I added them, it passed the tests I wrote for my code. static int printstring(Fmt *f, char *s) { int n; n = fmtrune(f, '"'); for(; *s; s++){ switch(*s){ case '\\': n += fmtstrcpy(f, "\\\\"); break; case '\f': n += fmtstrcpy(f, "\\f"); break; case '\b': n += fmtstrcpy(f, "\\b"); break; case '\n': n += fmtstrcpy(f, "\\n"); break; case '\r': n += fmtstrcpy(f, "\\r"); break; case '\"': n += fmtstrcpy(f, "\\\""); break; default: if(*s < 0x20) n += fmtprint(f, "\\u%04x", *s); else n += fmtrune(f, *s); } } n = fmtrune(f, '"'); return n; } Here's what I used to test it: #include <u.h> #include <libc.h> #include <json.h> void testJSON(char *s) { print("%s\n", s); JSON *j = jsonparse(s); print("%J\n", j); char *str = smprint("%J", j); assert(jsonparse(str) != nil); free(j); free(str); } void main(void) { JSON *j; char *str; JSONfmtinstall(); testJSON("{\"abc\": \"\"}"); testJSON("{\"abc\": \"hello\"}"); testJSON("{\"abc\": \"\\\"hello\"}"); testJSON("{\"abc\": \"hello\\\"\"}"); testJSON("{\"abc\": \"he\\\"llo\"}"); testJSON("{\"abc\": \"\\\"he\\\"llo\\\"\"}"); testJSON("{\"abc\": \"hello\\t\"}"); exits(""); } ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [9front] libjson can print invalid json 2022-11-18 14:37 ` Dave MacFarlane @ 2022-11-18 14:52 ` Dave MacFarlane 0 siblings, 0 replies; 4+ messages in thread From: Dave MacFarlane @ 2022-11-18 14:52 UTC (permalink / raw) To: 9front I was curious about keys and it looks like there's also a bug where they're not being properly escaped. Here's a diff that fixes that as well. cpu% git/diff . diff 30c5296f32b87d83529d772732726891e1261c9c uncommitted --- a/sys/src/libjson/printjson.c +++ b/sys/src/libjson/printjson.c @@ -7,6 +7,32 @@ static int printobject(Fmt*, JSON*, int); static int +printstring(Fmt *f, char *s) +{ + int n; + + n = fmtrune(f, '"'); + for(; *s; s++){ + switch(*s){ + case '\\': n += fmtstrcpy(f, "\\\\"); break; + case '\f': n += fmtstrcpy(f, "\\f"); break; + case '\b': n += fmtstrcpy(f, "\\b"); break; + case '\n': n += fmtstrcpy(f, "\\n"); break; + case '\r': n += fmtstrcpy(f, "\\r"); break; + case '\"': n += fmtstrcpy(f, "\\\""); break; + default: + + if(*s < 0x20) + n += fmtprint(f, "\\u%04x", *s); + else + n += fmtrune(f, *s); + } + } + n = fmtrune(f, '"'); + return n; +} + +static int printarray(Fmt *f, JSON *j, int indent) { JSONEl *jl; @@ -41,7 +67,8 @@ for(jl = j->first; jl != nil; jl = jl->next){ for(i = 0; i < indent; i++) fmtprint(f, "\t"); - r += fmtprint(f, "\"%s\": ", jl->name); + r += printstring(f, jl->name); + r += fmtprint(f, ": "); r += printjson(f, jl->val, indent); r += fmtprint(f, "%s\n", jl->next != nil ? "," : ""); } @@ -65,7 +92,7 @@ return fmtprint(f, "%f", j->n); break; case JSONString: - return fmtprint(f, "\"%s\"", j->s); + return printstring(f, j->s); break; case JSONArray: return printarray(f, j, indent+1); ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-11-18 14:53 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-11-17 21:52 [9front] libjson can print invalid json Dave MacFarlane 2022-11-18 4:30 ` ori 2022-11-18 14:37 ` Dave MacFarlane 2022-11-18 14:52 ` Dave MacFarlane
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